摘要:

AUGUST, 1906. Vol. XXXI., No. 365. CEED THE ANALYST. NGS OF THE SOCIETY OF PUBLIC A YSTS. ON THE PRESENCE AND DETECTION OF CYANOGEN IN JAVA, BURMA, AND HARICOT BEANS. BY R. R. TATLOCK AND R. T. THOMSON. (Read at the Meeting, May 2, 1906.) As we had to deal with this question in the recent poisoning of cattle by “Java ” beans, we have thought it might be of interest to put on record the result of our examination €or cyanogen compounds of “Java ” and other beans, as well as of peas of various kinds. As a fairly full report with regard to the poisoning cases in Scotland is given in the March and April numbers of the Journal of the Board of Bgricultzwe, we shall not refer further to these, nor, indeed, to anything directly connected with them, but shall confine our attention to the various specimens which we procured for experiment.For the determination of cynnogen we employed the method which Professor Dunstan used - namely, extracting the glucoside with alcohol, distilling off the latter, decomposing the former with hydrochloric acid, and distilling off the hydro- cyanic acid (the Agricultural Ledger, NO. 2, 1905). For the detection of the hydro- cyanic acid we made a mash of about 10 grams of the ground beans with 20 or 30 C.C. of warm water in a small stoppered bottle and kept at 40° to 50° C. for half an hour, then applied a modification of the Schonbein test. This consisted in holding in the vapour in the bottle a piece of filter-paper, which had been first dipped in a ‘0.2 per cent. tincture of guaiacum resin, and then in a 0.1 per cent.solution of copper sulphate, when the paper assumed a fine blue colour almost immediately, if hydro- cyanic acid was present. It is important that the blue colour should be rapidly developed, as the prepared paper slowly assumes a blue tint when exposed to the air, and this might be mistaken by careless observers for the effect of hydrocyanic acid. A good plan, therefore, is to prepare two slips of paper simultaneously, insert one into the vapour to be tested for hydrocyanic acid, and simply expose the other to the air, when a comparison will decide the question. If this plan is adopted no mistake can be made. In applying the Schonbein test it is generally directed to dip the filter-paper in a 10 per cent. tincture of guaiacum resin, and dry before dipping in the 0.1 per cent.solution of copper sulphate. On drying the paper, however, it250 THE ANALYST* always assumes a blue tint, and thisl vitiates its application to the detection of hydrocyanic acid, In consequence of this defect we have modified the test as described above. It should be noted that, as a rule, hydrocyanic acid (if present) can be detected after half an hour’s warning; but where no positive result is obtained, the bottle should be closed and allowed to stand at the ordinary temperature for several hours, in order to allow the hydrocyanic acid to accumulate by the gradual action of the enzyme contained in the bean on the cyanogenetic glucoside. After deciding the method of procedure, we, in the first place, examined several specimens of Java beans, and found from 0-027 to 0.137 per cent.of hydrocyanic acid, this being, of course, understood to exist in the beans in the form of an amygdalin-like glucoside. These results practically agree with those of the unculti- vated variety examined in the Scientific and Technical Department of the Imperial Institute. I n order to determine whether there was really any difference as regards cyanogen contents in beans of different colour, we obtained an average sample, weigh- ing about 3 pounds, of a lot of Java beans, and separated them into five different kinds. These consisted of white, brown of various shades, speckIed, chiefly brown and white, with a few purple and white, purple of various shades, and black beans. The sample was composed of these as follows : White beans ...... ... 1 . . ... ... Brown beans ... ... ... ... ... ... ... Speckled beans ... ... ... . . . ... Purple beans ... ... ... ... ... ... Black beans ... ... ... ... ... ... These were tested separately with the following results : White beans ... ... ... ... ... ... Brown beans ... ... ... ... ... ... Speckled beans ... ... ... ... 4 . . Purple beans ... ... ... ... ... ... Black beans ... ... ... ... ... ... Average ... ... ... ... ... ... Per Cent. ... 9 ... 34 ... 33 ... 20 ... 4 100 -_ Hydroeyanic Acid. Per Cent. ... 0-027 ... 0-038 ... 0.038 ... 0.031 ... 0.042 ... 0*0368 --_ From these results alone it might appear that the white variety con6ained the least, and the black the most, hydrocyanic acid ; but this distinction does not really hold good, although it has been held that white contains the least, and purple the most, of that ingredient. Other tests we have made showed in brown beans 0.072, and in black beans only 0.029 per cent.of hydrocyanic acid, so that the generalization as to the quality of the bean according to its colour is of no value whatever, I t has been stated that the cyanogen was contained in the husk and not in the kernel of the bean, but this opinion or assumption we have proved to be quite untenable. We carefully decorticated a small specimen of black beans, and foundTHE ANALYST. 251 that the husk was equal to about 10 per cent. of the whole, while the percentage of hydrocyanic acid in the decorticated portion was 0.030 per cent., and that in the husk only 0.003 per cent.We also procured a large specimen of decorticated beans, and the corresponding husks, from the mixed varieties, and found in the decorticated portion 0.061, and in the husks 0.006 per cent. of hydrocyanic acid. I t is thus apparent that the kernel contains at least ten times as much hydrocyanic acid as the husk, so that the statement we have referred to is not borne out by fact. It has also been suggested that it is the small, rounded beans that contain the hydrocyanic acid, but our experience does not bear this out even in the slightest degree. Having dealt with the Java beans, we next procured specimens of various kinds of bean and pea, and tested them for hydrocyanic acid, with the following results, which include also the average weight of the beans : English beans ...... ... Smyrna beans ... ... ... Large haricot beans ... ... Large haricot beans ... ... Small haricot beans (Rangoon) Small haricot beans ... ... Small haricot beans ... ... Small haricot beans (Chili) I . Gram ... ... Calcutta white and gray peas Odessa and Mutter peas ... Morocco beans ... Java beans ... ... Rangoon or Burma beans ... ... Paiyin beans ... ... ... ... ... Hydrocyanic Acid. Per Cent. ... none ... none ... none ... 0.027 to 0.137 ... 0.005 ... none ... 0.009 ... 0.006 ... 0.001 ... none ... none ... none ... none ... none ... none Number of Beans in 100 Grams. ... 170 ... 100 ... 272 ... 368 ... 64 ... 78 ... 384 ... 420 ... 448 ... 228 ... 1960 - ... I ... I ... - . I , The haricot beans (both small and large) mentioned above were obtained from different sources, and were all sold for human food.The sample containing 0.001 per cent. of hydrocyanic acid was purchased by ourselves in a grocer’s shop in Glasgow. From the above table we have further and most conclusive proof that it is a mistaken idea that the white bean is free from the cyanogen COmpoUnd, as the latter was present in three specimens of the white haricot bean, which is almost certain to be a, cultivated variety. I t will be observed that, the specimen of the ordinary (or coloured) Rangoon or Burma bean given above contains only rather more than half that contained in one specimen of the small white haricot beans. I n conclusion, we may note the effect of boiling the unground beans with water, and of mashing the ground beans with warm water.In carrying out the former experiments the three samples of small haricot beans containing hydrocyanic acid were steeped overnight with water and boiled until thoroughly cooked. They were then allowed to cool, beaten up with water, and the modification of Schonbein’s test applied, but hydrocyanic acid could not be detected in any of them. The hydrocyanic acid was now determined in the beans originally containing 0.009 per cent., after this treatment, and 0*002 per cent. was found. These results show clearly that a large252 THE ANALYST. proportion of the cyanogen compound and the d o l e of the enzyme have been destroyed by the boiling, but whether the amygdalin glucoside is harmless, seeing there is no enzyme present to produce hydrocyanic acid, is a question with which we cannot deal.In order to corroborate these results, Java beans containing 0.038 per cent. of hydrocyanic acid were steeped and boiled in the manner described ; but after this treatment no hydrocyanic acid could be detected by the modification of the Schonbein test, although 0.019 per cent. in the form of the glucoside was actually present. The result is entirely different when cold or warm water, as applied in the test referred to, is mixed with the ground bean. I n this case we found that in two or three days practically the whole of the cyanogenetic compound was decomposed, and the cyanogen in it liberated in the form of hydrocyanic acid. DISCUSSION. Dr. VOELCKER remarked that Professor Dunstan drew a clear distinction between the white and the coloured beans, and spoke of the white beans as being cultivated and as containing no cyanogenetic glucoside, whereas the speckled and purple beans did contain one.He was inclined to think, however, that this was an assumption rather than the result of actual experiment, and accordingly the present paper, if the beans dealt with were botanically the same, would be of considerable value. Mr. HENDRICK said that he had had occasion to examine a good many samples of these Java beans, and had done a little investigation on lines somewhat similar to part of that recorded in this paper. His results, generally speaking, mere in accord with those of the authors. Every specimen that he had examined of these so-called Java beans, zl great many thousands of tons of which had been imported into Europe during the last year or two, had yielded hydrocyanic acid in relatively large quantity.The beans varied very greatly in colour, even from bag to bag of the same consign- ment. In some cases white beans were more numerous than those of any other colour; in other cases the majority of the beans were black. He did not find, however, any corresponding variation in the amount of hydrocyanic acid, though, generally speaking, the darker beans contained a little more hydrocyanic acid than the light ones. He was not satisfied that the whole of the hyhrocyanic acid which it was possible to produce from the beans was obtained by extracting the glucoside with alcohol, which wits, he understood, the method used by the authors of this paper.I n a, few experiments which he had made he had found that mere soaking of the ground beans in water and subsequent distillation yielded, in every case that he had tried, a larger quantity of hydrocyanic acid than was obtained by the alcohol extraction method. He also had de-husked a sample of the beans, and had not obtained any hydrocyanic acid from the husks; it was all contained in the inner part of the beans. I t had been stated that where the beans had been washed before being used there had been no poisoning. Through the kindness of certain large dealers he had been able to visit some mills where the beans were thus treated, and had seen the whole process. The washing process was a very brief one, and though it removed much dirt, it did not do Inore than clean the outside of the bean, and could not affect the amount of cyanogenetic glucoside present.His difliculty was toTHE ANALYST, 253 explain why there had not been far more cases of poisoning. Great quantities of the beans had gone into consumption. He personally knew of cases in which beans, of which samples from the same parcel yielded a large proportion of hydrocyanic acid, had been fed daily for weeks to cattle without ill-effect. I n other cases poisoning had occurred at once, and large numbers of animals were lost, The poisoning seemed to be, so to speak, sporadic, and he felt convinced we had still something to learn as to its cause. Mr. ESTCOURT said that he had been told by a miller near Manchester of certain beans which had poisoned a considerable number of cattle.These beans were described as (‘ Indian mutter.” Mr. HENDRICK said that he had examined what were known as ‘( mutter peas,” and had not found them to yield any hydrocyanic acid. I t was known, however, that these peas sometimes caused poisoning of a different kind (see a paper by Dr. J. A. Voelcker, ANALYST, xix., 102). I n some cases the beans had been given in the form of dry meal, in some cases they had been soaked, and in some cases steamed. He had always found it quite easy to detect the bydrocyanic acid in these beans by smell, after soaking the meal in water for a short time, Dr. LEATHER said that there was no doubt that these various beans, those from Burma especially, did contain a cyanogenetic glucoside, though it was not yet certain whether this was identical with the phaseolunatin of Professor Dunstan.It is uncertain, also, what the exact botanical nature of these beans is. They seem to be a mixture of species, but in India nearly all the crops are mixed. He thought, from what he had seen of these beans, that they probably all belong to the same genus, but it was not certain whether Professor Dunstan’s statement as to Phuseolus Zuinutus is generally correct. Probably it is correct for the plant that Professor Dunstan operated on, but it is not certain that all these Burmese beans are the same. He had found a cganogenetic glucoside in various Indian beans, and its presence seemed to be very common in leguminous plants in the East. The quantity of prussic acid obtainable varied considerably.It is very much to be desired, of course, that further knowledge should be obtained as to the physiological action of the glucoside itself. It is easy to understand the production of prussic acid by grinding up and soaking the beans in water, because these cyanogenetic glucosides are almost always associated with enzymes capable of hydrolysing them; but whether such hydrolysis would necessarily be brought about by the enzymes of the digestive organs is another question altogether, and, as far as he was aware, no work has been done in that direction. It seems very possible that the erratic effects of the beans might be explained by variations in the degree to which hydrolysis results from digestive action. In one of the first references made to him in relation to these Burmese beans, it was stated that the beans were consumed regularly by the prisoners in Burmese prisons.All that food was cooked, so that the enzyme in it was certainly destroyed; and it remained then for the enzymes of the digestive juices to hydrolyse the glucoside if they could. Apparently, as a rule, they could not. I n the case of stock-feeding it is clearly necessary that such beans shall first be cooked, so as to destroy the enzyme; but it is to be recollected that the glucoside is not destroyed by a temperature of looo C.THE ANALYST. Mr. HENDRICK asked whether Dr. Leather knew of any case of poisoning from Burma beans. Dr. LEATHER said that he only knew of cases of poisoning that had occurred in this country; none had occurred in India. Mr. HENDRICK said that, as far as he knew, there had been no case of poisoning by Burma beans. I t was at first stated in the newspapers that some of the beans which had caused poisoning were from Burma, but in every case, so far as he was aware, it was found on investigation that they were Java beans. The latter were different from Burma beans. Both seemed to be varieties of PhaseoZus, though he did not know the exact species. The Burma beans were quite uniform. Dr. LEATHER : No, they vary very much indeed. M i . HENDRICK said that all the samples which he had seen of what was described as “Red Burma Beans” were red mottled beans, very similar to one another in appearance, whereas the Java beans he had seen varied greatly in colour and appearance. These red Burma beans have been imported in large quantities for many years past, and are extensively used as cattle-food in this country, but he had never heard of an authenticated case of poisoning arising from their use. NOTE TO ISC CUSS ION BY THE AuTHoRs.-our experience differs from that of Mr. Hendrick with respect to the extraction of the glucoside with alcohol, as this method gave more cyanogen than that by simply soaking the ground beans with water and distilling ,

ISSN:0003-2654    

DOI:10.1039/AN9063100249

出版商:RSC    

年代:1906

数据来源: RSC

摘要:

254 THE ANALYST. ON THE POLENSKE METHOD FOR THE DETECTION OF COCOANUTOIL IN BUTTER. BY S. RIDEAL, D.Sc., F.I.C., AND H. G. HARRISON, &!LA., A.I.C. (Read at the .Meeting, May 2, 1906.) THE Polenske method for the detection of cocoanut oil in butters depends upon two conclusions at which he has arrived : 1. That in the distillation of the fatty acids, the quantity of insoluble volatile acids bears a strict relationship to the soluble volatile acids. 2. That a mixture with cocoanut oil reduces the “soluble” figure, but at the same time increases the insoluble ” figure to such an extent that each per cent. of cocoanut oil gives 0.1 C.C. *i alkali in excess of the figure obtained from a genuine butter giving the same (‘ soluble ” figure. To test these conclusions a number of pure English butters have been examined, as well as butters of unknown origin. We find that the distillates from pure butters do not give the ‘‘ soluble )’ and ‘6 insoluble ” figures in such a strict ratio, but that, starting with a, pure butter fat, and mixing it with cocoanut oil, the relative increase in the “ insoluble ” figure practically agrees with Polenske’s results.THE ANALYST.255 By plotting his ‘( insoluble ” figures against ‘‘ soluble ” a smooth curve is obtained and none of the thirty-one points lie far from the curve; Our butters show much more divergence, but by taking an average curve in the two cases, the English butters give a curve lying considerably below Polenske’s, and the curve for the unknown butters lies between the other two.Polenske‘s highest Reichert-Meissl value is only 30.1, while both the other series give higher values in this direction. The following results have been obtained by us : PURE ENGLISH BUTTERS.. JUNE AND JULY. ~ Pure Butter Fat. I - -__ County. 1 Nurnher of Cows ’ I ~ , Soluble C.C. Fw Insoluble C.C. Fw ~ I Devonshire . . Huntingdonshire Surrey ... ... Somerset . . . ... Y ’ * * - ... Devon shire . . . Somerset . . . ... ? 35 4 7 5 or 6 several 1 4 ? ? 3 12 ’ 31.2 28-9 29.35 30-15 29.85 ~ 31-6 1 34-55 j 29.0 ~ 30-05 ! 29.5 I 31-25 I 2-05 1-85 1.7 1-85 1.85 1.85 1.6 2.15 1.7 1.8 1.65 1-95 Butter Fat + 20 per Cent. Cocoanut Oil. 26.7 26-85 27-15 26.3 26.3 26-55 When the first six of these were mixed with 20 per cent. of cocoanut oil giving insoluble ” values of 8-75 and 13.4, on the average the ‘‘ soluble ” figure was decreased by 3.4 and the (‘ insoluble ” figure increased by 2.3.In order to get an idea of the changes in the values which take place under varying conditions of season, food, etc., samples have been taken at fortnightly intervals from a Huntingdonshire dairy farm since August 14, 1905. These butters are made from the milk of about thirty-five cows, a number sufficiently large to eliminate variations due to period of lactation in the individual cows. I n each case the cows were milked within the week preceding the date given. soluble ” and256 R. M. Values. 27-28 28-29 29-30 30-31 31-32 32-33 33-34 34-35 THE ANALYST. FORTNIGHTLY SANPLES FROM SAME DAIRY. Average. Soluble C . C . Insolnble C . C . 27.88 1.33 28-70 1.53 29-36 1-77 30 -44 2.00 31.52 2.10 32.43 2.37 34.55 2.15 I - Date.... June 29, 1905 ... ... ... ... Aug. 14' ,, ... ... ... ... ... ... ... - ^ . ... 9 , 28 9 , ... sept. 11 7 , ... ... ... ... ... ,, 35 ), ... ... ... ... ... Oct. 9 7 , ... ... ... ... ... , 7 23 , ? - - - Nov. 6 ,, ... ... ... ... ... ,, 20 9 , ... ... ... ... Dee. 4 ,, ... ... ... ... ... 7 ) 18 ,, 15 ,, ... ... ... ... ... 9 7 26 7 , - . * 9 , 26 7 9 - * * ... ... ... ... ... ... ... ... ... ... Jan. 1, 1966 ... ... ... ... ... F:b. 12 ,, ... 29 ,, ... ... ... ... Mar. 12 ,, ... ... ... ... April 9 7 y ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... Soluble C.C. Tn. 28.9 29.55 28.5 27.95 27.8 29.2 32.1 30-7 32.9 30.1 31.75 30-5 30.25 31.8 32.3 31.25 31.8 29-05 30.8 Insoluble C.C.yi. 1.85 1." 1.2 1-3 1-35 1.35 2.3 2.2 2.05 1-75 2.2 2.1 2-25 2-1 2.75 2.3 2.5 2-3 2-4 Until October the cows were entirely on grass and out all the time, then they began to come in at night and have linseed and cotton-cake in addition. During November and December the cows were kept under shelter, and in addition to cake were fed with hay, oatmeal, and rabi. After December mangel-wurzel was sub- stituted for the rabi, and some of the cows began to go out for part of the day. The average results obtained from all these English butters are given in the curve. They were obtained by taking averages of the results lying within a range of 1 C.C. of soluble volatile acids as given in the following table : AVERAGE RESULTS FOR PURE ENGLISH BUTTERS.No. of Samples.C.C. 2~ alkali required to neutralise soluble volatile acids (Reichert-Meissl value). A, Polenske's curve for 80 per cent. butter-fat -t 20 per cent. cocoanut oil. D, English butter f20 per cent. cocoanut oil. E, Unknown butters. P, Pure English butters. B, I 2 90 7 7 9 7 f l O per cent. ,, (average). c, I 7 pure butters. 0 Average English butters. x Average unknown butters.258 THE ANALYST. In a similar manner the figures obtained from one hundred and three unknown butters, presumably genuine, were averaged as follows : AVERAGE RESULTS FOR 103 UNKNOWN BUTTERS. Average. No. of Samples. 1 R. M. Values. 1 Soluble C.C. 3 4 7 8 19 29 20 6 4 2 1 24-25 25-26 26-27 27-28 28-29 30-31 31-32 32-33 33-34 34-35 29-30 24.58 25-46 26.42 27.27 28.50 29.45 30.36 31.30 32.41 33-35 34.7 Insoluble c.c. 1.55 1-58 1-46 1.73 1.98 2-12 2.16 2-13 2-91 2.83 4-1 During the same period margarines were examined in the same way, but in no case gave an ‘‘ insoluble” value greater than 1 C.C. TG alkali ; and mixtures made with butter, margarine, and cocoanut oil gave figures which indicated the amount of cocoanut oil present, but no indication in themselves of margarine if a butter of high Reichert value were taken. Cheese fats examined by the same method, while giving, as is well known, the Reichert value higher than is general with butters, gave insoluble ” values which are in the same ratio to the (‘ soluble ” values as in the case of butters. DISCUSSION. The PRESIDENT (Mr. Bevan) asked whether the saponification was done with glycerin or with alcohol.The Polenske number, as was well known, differed con- siderably according to whether glycerin or alcohol was used, being, if he remembered rightly, higher with glycerin than with alcohol. Mr. HARRISON said that glycerin had been used, following the process as prescribed. Mr. E. R. BOLTON said that he had been particularly interested in this paper in so far as it related to cocoanut oil, with which he had had more experience than with butter. The results he had obtained were more or less in agreement with those now given, except that he usually found a higher insoluble acids figure, and a lower Reichert- Meissl value than the authors had. But he had obtained a Reichert-Meissl figure as high as 9 for cocoanut oil, whereas the highest mentioned by Polenske wag 7.7.He had also noticed that, as a rule, the figure for insoluble volatile acids in cocoanut oil was from 2.2 to 2-5 times the Reichert-Meissl value. It was difficult, however, to get samples of cocoanut oil that were perfectly normal. I n many cases the ( ( stearine ” mightTHE ANALYST. 259 have been removed, and some samples might contain palm kernel oil. It was, perhaps, worth noticing that palm kernel oil gave an average Reichert-Meissl figure of 5, the figure for insoluble volatile acida being 10. As far as the effect of different modes of feeding was concerned, the Polenske numbers seemed to come out very regularly. He did not know whether Polenske had made any notes as to the feeding of the cows in his investigations, but it was a matter of common experience that the use of cake did affect to a certain extent the composition of the butter-fat, and certainly cocoanut cake had some effect in many cases.Nr. HINKS inquired whether in any of these cases the ordinary Reichert-Wollny figure, as well as the Reichert-Meissl figure, hsd been determined in conjunction with the Polenske number. If so, it would be interesting to see what difference was made by the use of glycerin and by the more rapid distillation. Mr. HEHNER said that his experience was quite in agreement with that of the authors, that the relationship between the Polenske number and the Reichert-Wollny number was not in every case so definite that one could safely use it as the basis of a definite charge of adulteration. Broadly speaking, of course, it was agreed that the lower the Reichert-Wollny figure, the lower would be the proportion of insoluble volatile acids.Owing, however, to the varying circumstances under which butter was produced, one could not be guided by broad facts in particular cases. His own experience over some considerable time had been that the Polenske numbers shown by pure butter were about the same as those which the authors had obtained, and it would be seen that the difference between the authors’ curve for English butters and Polenske’s curve for pure butter-fat would allow a margin of about 10 per cent. for admixture. At one time it was thought that fluidity of the insoluble volatile acids indicated the presence of cocoanut oil, and that to a certain extent was true, but it was not universally true.I n the case of pure butter showing a low Reichert-Wollny figure the insoluble volatile acids were almost invariably solid. When a low Reichert- Wollny figure was associated with fluid insoluble volatile acids, and especially when the Polenske number exceeded 2, the proof of the presence of cocoanut oil was fairly definite. But in butters showing Reichert-Wollny figures of 25 or over, the insoluble volatile acids were in many caBes quite fluid. He did not think it safe to rely upon any single figure, however important it might be in itself. Cocoanut oil, as was well known, had a very low iodine value and a very low refraction, whereas genuine butter with a low Reichert-Wollny figure had almost invariably a high refraction and a high iodine value.I n this connection micro-polariscopic examination was of some impor- tance. I t was, however, beset by many pitfalls, and used alone would be worth nothing. I n the process suggested by Knud Jensen and Kirschner unfortunately the silver caprylate was too soluble, and the solubility too much influenced by tempera- ture and time allowed for the precipitation, to lead to reliable figures. Mr. ESTCOURT said that, from experiments with butter made in his own laboratory, in connection with some samples that were suspected of containing cocoanut oil, he had come to the conclusion that in genuine butter having Reichert number less than 29 the figure for insoluble volatile acids was rarely over 2. Mr: HARRISON, in reply, said that it must be agreed that between the figures they Then came the question of the state of the insoluble volatile acids.260 THE ANALYST. found and those of Polenske there was, as Mr. Hehner had said, an appreciable margin of possible adulteration. Polenske himself stated that nothing under 10 per cent. could be detected-that, of course, being the minimum, and each 1 C.C. of increase being taken as equivalent to 10 per cent. of cocoanut oil. Towards the end of the curve, however, there was a wider range of variation still, There wag, there- fore, considerable difficulty in making the process quantitative, apart from the question of the actual detection of cocoanut oil. If, however, they could satisfy themselves that this process was capable of detecting the presence of cocoanut oil with certainty, it might be possible to arrive at some approximate-estimate of the quantity. With regard to saponification, although the authors had only used glycerin, he should think that, as a rule, with alcohol a slightly higher Reichert- Meissl value would be obtained than with glycerin. The difference, however, would not be very great. He knew nothing about the Polenske value under these con- ditions.

ISSN:0003-2654    

DOI:10.1039/AN9063100254

出版商:RSC    

年代:1906

数据来源: RSC

摘要:

260 THE ANALYST. ABSTRACTS Prot eolysis OF PAPERS PUBLISHED IN OTHER JOURNALS. FOODS AND DRUGS ANALYSIS. in Cow’s Milk preserved with Formaldehyde. G. Tice and H. C. Sherman. (Jou/m. Awzer. Chem. Xoc., 1906, xxviii., 189-194.)-Analyses of samples of milk preserved with formaldehyde show that very considerable proteolysis takes place after some time, the albumin being largely digested before the amount of casein is appreciably reduced, though as digestion proceeds and the casein diminishes the proportion of nitrogen existing as albumin and syntonin changes but little, the increase appearing first in the proteoses, then in the peptones and amino-compounds. Only slightly more nitrogen was precipitated by phosphotungstic acid than by tannin, indicating the presence of only small amounts of diamino-acids.Relatively large amounts of proteoses have been found at a rather advanced stage in the digestion, result entirely different from that of bacterial digestion of milk. I n one case, while 95 per cent. of the casein had been digested, less than 4 per cent. of the original lactose was lost, as compared with milks preserved with sodium fluoride or salicylate or hydrogen peroxide, in which, after 25 to 30 per cent. of the lactose had been destroyed, no marked digestion of the casein was noticed, proving the effect of an added antiseptic in determining the character of the fermentation subsequently undergone. W. H. S. The Determination of Proteids in Milk. Trillat and Sauton. ( A m . de Chim. anal., 1906, vol. 11, pp. 205-207.)-The method is based upon the fact that formaldehyde renders the proteids of milk insoluble.Five C.C. of the milk are diluted to 25 C.C. with water, and the liquid boiled for five minutes, then treated with 5 C.C. of commercial formalin, boiled for two or three minutes longer, and allowed toTHE ANALYST. 261 ... ... ... Cow's milk 39.11 34.33 19.50 Ditto, with 10 per cent. of water Ditto, with 50 per cent. of water ... Goat's milk ... ... 36.64 Ass's milk ... ... ... 21-03 ... ... Colostral milk (cow) 11.00 On the Use of the " Silver Value " for the Deteetion of Cocoanut Oil in Butter. F. Jean. (Ann. de Chim. awl., 1906, vol. 11, pp. 121-124.)-The method devised by Wijsrnan and Reijst (ANALYST, xxxi., 158) has 'been tried by the author upon twelve samples of doubtful butter, and as the second silver value was invariably lower than the first, the conclusion arrived at was that the butters were abnormal, but free from cocoanut oil.On the other hand, the method of Muntz and Coudon (ANALYST, xxx., 155) gave ratios of 22 to 36, which, in conjunction with the other analytical values, pointed to the presence of cocoanut oil. Thus the following results were obtained with two of the samples : 1-1- I I Butter, No. 1 ,, No. 3 228 27-2 229 1 26-2 35 35 5.06 4.95 3 + 3 . zg 3 + 5% c) m 4-81 4-50 Mnntz and Coudon's Method. 0 0 + X 0 -3 I;, 2 4.81 4.50 1.76 1.14 36 26 Abnorm a1 Abnormal In order to determine the cause of these contradictory results, the author prepared mixtures of pure butter with 10 per cent. of a cocoanut-oil mixture in262 THE ANALYST. common use for adulterating purposes, and with 10 per cent.of a mixture in equal parts of cocoanut oil, karitb, butter, and lard, and obtained the following results : Adulterated Butter, No. 1 9 , ,, No. 2 32.0 ' 220 ' 26.4 32.5 1 216 1 26.7 4.72 4.69 The presence of the cocoanut oil (3.4 and 2.5 per cent. respectively) is here plainly shown by the ratio in Munte and Coudon's method, whereas from the silver values both samples would have been judged to be pure. Hence the author concludes that the method of Wijsman and Reijst can only be of value as a confirmative test, and that when it gives negative results cocoanut oil in admixture with other fats may still be present. C. A. M. The Characteristics of Karite Butter. F. Jean. ( A m . de Chim.aizaZ., 1906, vol. 11, pp. 201-203.)-KaritB or fulwar butter is extracted from the seeds of Bassia butyracea, a tree growing in the Himalayas and in the tropical zone of Africa. According to the author, large quantities of the seeds and of the fat are sent to England, the latter being used in the adulteration of butter, lard, and cocoa-butter. The kernels examined by the author had the following composition : Water, 10.05 ; fat, 35.49 ; soluble extractives, 26.44 ; tannin, 3.2 ; ash, 2.50 ; and cellulose, 22.52 per cent. The butter is a white, paste-like fat, with a slight odour and an astringent taste. I t can be purified by a method similar to that used in deodorizing cocoanut oil for food purposes. The following analytical values were obtained with a sample of the fat extracted with petroleum spirit and of fat prepared by the natives by crushing the nuts with water : Oleorefracto- Melting- Acid Saponifica- Iodine Reichert- Hehner Fat.y2h.at point. Value. tion ~ a l u e . Value. :.$$ ~~~~ Value. Extracted in Q C - laboratory +22" 30 - 175-176 - 2.6 - Asimported +18" 30 9 175 19.75 1.19 trace 91.2 The fat consisted of 69.28 per cent. of solid fatty acids, 21-92 per cent. of liquid The fatty acids, separated by Renard's Neither caproic nor caprylic acid was present in the acids, and 8-85 per cent. of glycerin. method, melted at 67.8" C. butter. C. A. &I. The Action of Flour, etc., on Hydrogen Peroxide. W. Bremer. (Zeit. Untersuch. Nahr. Genussm., 1906, xi,, 569-577.)-The author's experiments show that the method proposed by Wender (ANALYST, 1906, xxxi., 73) for the valuation ofTHE ANALYST.263 flours is at present of little use. The evolution of oxygen is erratic, equal weights of the same flour yielding varying volumes of gas, and the quantity is not proportional to the amount of flour employed, or to the percentage of bran in the flour. The power of decomposing hydrogen peroxide is diminished if the flour be heated previously to a temperature of 98' C., a moist heat having more effect than a dry heat. As both the aqueous extract and the insoluble residue, obtained on extracting bran with water, decompose hydrogen peroxide, the assumption is raised that more than one constituent of the bran is capable of causing the decomposition. The presence of mercuric chloride or of hydrochloric acid inhibits the reaction, as does also that of alcohol.Whilst well-washed gluten decomposes hydrogen peroxide to a slight extent, no action was noticed in the case of aqueous solutions of diastase. w. P. s. Formic Acid as a Preservative of Lemon-Juice. Von Kiittner and Ulrich. (Zeit. ofentl. Chew., 1906, xii., 201-207.)--The deterioration of fresh lemon-juice due to the formation of acetic acid may be prevented by the addition of from 0.1 to 0.4 per cent. of formic acid. The addition, of course, increases the acidity of the juice, and the results of experiments are given which show that the formic acid distils over quantitatively with the other volatile acids present in the juice. w. P. s. Composition of Tomatoes and Tomato-Juice. W. Stuber.(Zeit. Unter- such. Nahr. Genussm., 1906, xi., 578-581.)-The following results were obtained on the analysis of two samples of tomatoes and their respective juices : -_ - Water . . . ... ... ... Ash ... ... ... ... Alkalinity of ash (c.c. acid) ... Nitrogen ... ... ... ... Petroleum spirit extract ... Sugars (after inversion) . . . Free acid (as citric) . . . ... Phosphoric acid (P,05) . . . ... ... Fruit, 1. _____~ Per Cent. 94.52 0.116 0.50 4.62 0-06 2.51 0.41 0.044 Fruit, 2. Per Cent. 95.13 0.159 0-63 5.50 0.07 3.21 0.48 0.059 Juice, 1. Per Cent. 96.00 0-098 0.50 5.20 2.34 0-60 0.031 - Juice, 2. Per Cent. 96.19 0.088 0.63 6.00 1.96 0.61 0.039 - Juice, 3. Per Cent. 95.48 0.128 0.65 6.40 2-53 0.46 0.025 - The sample of juice No. 3 was obtained from Canadian tomatoes, the other Tartaric, malic, and succinic acids could not be samples being of German origin.detected in any of the samples. w. P. s. Determination of Tale on Rice, Pearl-Barley, etc. R. Kriizan. (zeit. li'ntersuch. Nahr. Genuswz., 1906, xi., 641-650.)-The quantity of talc present as a coating on rice, pearl-barley, or other grain can only be correctly determined by directly weighing the mineral after detaching it from the grains. As the mineral is264 THE ANALYST, readily attacked by hydrochloric acid, especially after ignition, the method proposed by Matthes and Muller (ANALYST, 1905, xxx., 206) is untrustworthy, and methods based on the determination of the magnesia in the ash of the sample (the magnesia being subsequently calculated into talc) give incorrect results, owing to the varying composition of the mineral itself, and to the magnesia natural to the grains.The author, therefore, employs a process in which a weighed portion of the sample is heated with a little hydrogen peroxide and dilute ammonia; bubbles of gas form between the grain and its coating, and completely loosen and remove the latter. The turbid liquid is decanted, the grains are shaken and washed several times with water, and the total liquid then rendered acid with hydrochloric acid, and the organic matter oxidized by the addition of a few grams of chromic acid. The mixture is heated to boiling, filtered, and the residue is washed with water and ignited at the lowest possible temperature. The weight of residue obtained represents the amount of talc in the portion of the sample taken.Besides talc, other minerals, such as mica and certain clays, are used for coating grains. (Cf. '' Facing of Rice," this vol., p. 40.) w. P. s. The. Determination of Alcohol in Chloroform. M. Nicloux. (BUZZ. SOC. Chim., 1906, xxxv., 330-335.)-A small proportion of alcohol is commonly added to chloroform as a preservative. I t can be separated by shaking 5 C.C. of the sample with 20 C.C. of water, which extracts the whole of it, and it can then be determined in the supernatant aqueous layers by the author's bichromate method. Five C.C. of this alcoholic solution (containing not more than 1 part of alcohol in 500) are mixed in a test-tube with 0.1 to 0-2 C.C. of a solution of potassium bichromate (19 grams per litre), and then with pure sulphuric acid (66" B.), which, when added in suEcient quantity (4.5 to 6 c.c.) decolorizes the solution.The liquid is now gradually titrated with the bichromate solution, being shaken and gently heated after every addition, until the colour changes from greenish-blue to a permanent greenish-yellow. The change is most readily recognised in solutions containing less than 0.2 per cent. of alcohol. I t is advisable to make a second determination in which the amount of bichromate used in the first experiment, less 0.1 C.C., is run in at once, the sulphuric acid added, and the liquid boiled for a moment. The contents of the tube ought to remain greenish-blue, whilst in another determination in which 0.1 C.C. more than the first reading is added, the colour should change to greenish- yellow. The number of C.C. consumed, divided by 1,000, gives the amount of absolute alcohol in C.C. per C.C. of solution. When the proportion of alcohol is less than 0.1 per cent. it is best to double the strength of the bichromate solution. Six samples of chloroform examined by this method were found to contain from 1.4 to 10.4 C.C. of absolute alcohol per litre. Test experiments with chloroform containing known quantities of alcohol showed that the results were concordant and accurate. C. A. M.

ISSN:0003-2654    

DOI:10.1039/AN9063100260

出版商:RSC    

年代:1906

数据来源: RSC

摘要:

THE ANALYSTI 265 ORGANIC ANALYSIS. Analysis of Sugar Mixtures. C. A. Browne. (Jozwn. Amer. Chem. Soc., 1906, xxviii., 439-453.)-Since the weights of two different sugars reducing the same amount of copper bear a constant ratio to one another, the differences in the reducing powers of the various sugars can be very simply expressed by determining this ratio for each sugar, compared with dextrose as a standard. These constants are termed the ‘‘ dextrose ratios ” or “ equivalents,” and based on the conclusions that (1) the266 THE ANALYST. dextrose equivalent of a mixture of reducing sugars is equal to the sum of the dextrose equivalents of the individual sugars (which the author has proved, notwith- standing statements to the contrary); and (2) the polarization of a, mixture of sugars is equal to the sum of the polarizations of the individual sugars present, formulae are developed which enable the percentage composition of a mixture of any two sugars, or of three sugars, one of which is sucrose, to be ascertained from determina- tions of the copper-reducing power of the mixture and of its polarization.Two sources of error arise in such separations, due to (1) the slight reducing action of sucrose upon Fehling’s solution, and (2) the change in rotation of laevulose in neutral and acid solution. I n some experiments with a mixture of dextrose and sucrose, the error due to the first-mentioned cause is found to be inversely proportional to the amount of dextrose present, and the following correction gives concordant results : Divide the grams of sucrose in the 25 C.C.of solution to be analysed by Allihn’s method by the mgms. of dextrose found +40, and subtract the quotient in grams from the dextrose found. The correction for the second source of error depends upon the concentration of the acid used for inversion and the dilution of the sugar solution; for 10 C.C. fuming HCl (specific gravity 1.18) and 100 C.C. of sugar solution the correction is 0,036 per cent. for each percentage of IEvulose. Experi- ments on a number of known mixtures of various sugars have proved the accuracy of the method. W: H. S. On the Colour Reactions of Sesame Oil. P. Soltsien. (Cham. Rev. Fett. a. Haw-Ind., 1906, xiii., 138.) - Further experiments have confirmed the author’s conclusion that the furfural reaction and the tin reaction of sesame oil are not due to one and the same substance.Both compounds can be extracted by shaking the oil with alcohol of 90 per cent. strength, but thorough extraction with hydrochloric acid of specific gravity 1-125 removes the substance that gives the furfural reaction, whilst the oil still gives the tin reaction as strongly as before. The tin react,ion is also quite independent of Bishop’s reaction. Hence, if a sesame oil for any reason gives neither the furfural nor Bishop’s reaction, it may still be possible to identify it by the tin reaction (see ANALYST, xxvii., 363 ; xxviii., 298, 364). C. A. M. On Indian Ghedda Wax. Georg Buchrer. ( C h m Zeit., 1906, xxx., 528.) -The author takes exception to the statement of Dr. J. Konig ( ‘ I Die Untersuchung landwirtschaftlich und gewerblich wichtiger Stoffe,” ed.1906, p. 939), that the Ghedda wax of India is not to be regarded as real beeswax. The matter is of importance, since for church use only candles made from beeswax may be used. Ghedda wax is produced by three species of bees, two of which-Apis dorsata and ApZs fZorea -stand evolutionally directly before the European ApZs meZZi$ca, whilst the third-Apis indica or fasciata-appears to be a variety of Apis meZli$ca. Ghedda wax is qualitatively of the same composition as ordinary beeswax, but differs from it quantitatively, the amount of free cerotic acid being very much less and theTHE ANALYST. 267 This is shown in the quantity of esters very much higher in the Indian wax. following table : Source .___--.~__ Apis dorsata .. . . (23 samples) Apis Jlorea . . . (5 samples) . . . Apis indica ... (7 samples) Apis mellifica . . . Average Maximum Minimum Average Maximum Minimum Average Maximum Minimum Average Maximum Minimum 63.1 67.0 60.0 64.2 68.0 63-0 63.25 64-0 62.0 63.25 7-0 10-2 4.4 7.5 8-9 6.1 6.8 8.8 5-0 20.0 -- 96.2 105.0 75-6 103.2 130-5 88.5 96.2 102.5 90.0 95.0 todine Value (Hiibl). --- 6.7 9-9 4.8 8.0 11.4 6.6 7.4 9.2 5.3 7.5 11.0 4.0 The author is of opinion that Ghedda wax is to be regarded as a true beeswax, and as such admissible for church use. A. G. L. The Reaction of Mercuric Acetate with Camphene and Pinene. L. Bal- biano. (Reale Accad. d i Lincei; through Phzarm. Journ., 1906, vol. 76, p. 641.)- When equal volumes of benzene and an essential oil containing camphene are shaken with a 25 per cent.solution of mercuric acetate, and allowed to stand for thirty days, a crystalline compound, CloHl,0(HgC2H,0,),, is formed which is insoluble in water, alcohol, and ether. When the crystals are suspended in water and treated with a current of hydrogen sulphide they regenerate camphene. When pinene is subjected to prolonged contact with aqueous mercuric acetate solution, the reaction is quite diff'erent, A6 oxymenthenone being formed. w. P. s. A New Method for the Determination of Nitrogen in Nitrocellulose. M. Busch. (Chem. Ztg., 1906, xxx., 596.)-The nitrocellulose is saponified with caustic alkali in the presence of hydrogen peroxide, which prevents reduction of the nitrate by the cellulose further than to nitrite.On acidifying in the presence of hydrogen peroxide, the nitrite is also quantitatively oxidized to nitrate. The determination is then completed by adding (' nitiron,'' and weighing the nitron nitrate (C,oH,,N,~HNO,). A. G. L. Extraction of Tanning Materials for Analysis. F. P. Veitch and H. H. Hurt. (Journ. Anzer. Chem. Soc., 1906, xxviii., 505-512.)-Further experiments with the continuous extractor confirm the conclusion that this extractor gives the most complete extraction, all soluble constituents being removed by it in larger quantities than by other extractors. It has been stated that with sumac and canaigre268 THE ANALYST. the temperature must be kept at from 50" to 60' C. until at least half the volume of the extract is obtained ; but these materials were extracted satisfactorily in the con- tinuous extractor with from 200 to 300 C.C.of water below 100' C., the extraction being completed at steam heat. All materials should be ground to pass at most a millimetre sieve, and extraction should be continued for at least sixteen hours, pre- ferably for twenty-four hours. W. H. S. Strychnine Tannate and its Application to the Analysis of Tanning Materials. S. R. Trotman and J. E. Hackford. (Leclerrnarkt, CoZZegium, 1906, 69 ; through Chenz. Zeit., 1906, xxx., Rep. 167.)-The tannate of strychnine is almost insoluble in water, whilst the gallic acid compound is easily soluble. In making an analysis, the tanning material is extracted with alcohol. The extract, which should contain about 0.5 gram of active substance, is evaporated to 50 c.c., and made up to 100 C.C.with water. The liquid is filtered from the resinous bodies, and 25 C.C. of the filtrate are diluted with water, after which 0.25 gram of strychnine dissolved in 50 C.C. of alcohol and 50 C.C. of water is added, and the whole diluted to 250 C.C. with water. The precipitate is filtered off on to a Gooch crucible and dried in vacuo. Experiments with pure tannin showed that if an excess of strychnine is present, the tannate contains 1 molecule of strychnine for every 1 molecule of tannic acid. A. G. L. The Determination of Uric Acid in Urine. G. Guerin. (Jouwz. Pharnz. Cham., 1906, xxiii., 516, 517.)-One gram of anhydrous sodium carbonate is dissolved in 120 to 125 of the urine and the resulting precipitate of phosphates separated by filtration.One hundred C.C. of the filtrate are mixed with 25 C.C. of a solution of ammonium nitrate (50 grams in 100 c.c.), followed by 5 C.C. of ammonia solution, and allowed to stand until the next day, when the uric acid will have been quantitatively precipitated 8;s ammonium urate. The precipitate is collected, washed with a solution containing 10 per cent. of ammonium nitrate and 1 per cent, of ammonia, and transferred with the aid of a jet of water into an Erlenmeyer flask. The turbid liquid (about 100 c.c.) is mixed with 40 C.C. of sulphuric acid (1 : l), heated to 50° C., and titrated with a standard solution of potassium permanganate (1.5 gram per litre), the flask being shaken after each addition. The number of C.C.consumed multiplied by 0.00356 gives the amount of uric acid in 100 C.C. of the urine, The method is directly applicable to urines containing albumin. Urines that give a deposit of urate ought to be slightly heated on the water-bath and shaken until the sediment dissolves, before the addition of the sodium carbonate. C. A. M. Estimation of Ammonia in Used Lime Liquors. H. R. Procter and D. McCandlish. (JozLT?~. XOC. Chem. h d . , 1906, xxv., 254256.)--A current of air, freed from carbon dioxide and ammonia by passage through U-tubes filled with NaOH and H,SO,, is rapidly drawn, by means of a water-pump, through the ammoniacal liquor contained in a ' 6 glass worm " immersed in a water-bath at 90" C., and thence through a U-tube containing a known volume of standard acid.Frothing is obviated, and the time required reduced from one hour to thirty minutes byTHE ANALYST. 269 replacing the " glass worm " by the following apparatus : A piece of glass tubing, A (about &-inch bore), is drawn out to a fine point at one end, which is bent up as shown in the figure. Over this point is fixed, by wiring round a piece of cork, a second tube, B, of the same diameter as A, but slightly widened at the end. The tubes are then fitted in a wide test-tube (10 inches by 2 inches) containing sufficient water to cover their junction, the long arm of A passing through a two-holed rubber stopper, FIG. 1. and being connected with U-tubes containing NaOH and H,SO, for purifying the air. Through the other hole of the stopper is a short piece of bent glass tubing making connection with a U-tube containing 30 to 40 C.C.of & acid, which in turn is attached to the pump. The tubes A and B are so adjusted that the passage of the air came8 a continuous stream of water up to B, air also escaping from the bottom of B and rising outside it. The test-tube is filled with broken glass up to within 2 inches of its top, and over the end of B ip, placed the inverted head of a thistle funnel, the aperture where the stem was connected having been carefully sealed. The tube is then placed in a water-bath at 90" C., 50 C.C. of the lime liquor introduced into A through a filter funnel, and slight suction applied, whereby the liquor is continuously raised to the top of B and thrown back by the thistle funnel upon the broken glass, whence it runs.back to the bottom of the tube, the ammonia being thus completely drawn off within thirty minutes. W. H. S. Notes on the Determination of Ash in Elementary Organio Analysis, (Chem. Ztg., 1906, xxx., 567.)-The author finds that in Fritz von Konek.270 THE ANALYST. analysing coals the amount of ash left in the carbon and hydrogen determination (carried out in an electrically-heated furnace) is always higher than that given by the usual method of ashing the sample in a platinum crucible in the air. He shows that platinum boats increase in weight (up to 0.8 mgm.) on ignition in oxygen, coming back to their original weight on prolonged heating in air. Many substances (calcium carbonate, iron oxides, etc.) also behave differently according as to whether ignited in oxygen or air. Finally, the quantity taken for the elementary analysis is so small that it is very difficult to obtain a fair sample as regards ash. For all these reasons the author prefers to take the usual ash figure obtained by burning 1 or 2 grams of the fuel in a crucible. A. G. L. Combustion of Halogen Compounds in Presence of Copper Oxide. C. J. Robinson. (Amer. Chem. Journ., 1906, vol. 35, pp. 531-533.)-The need for a separate combustion tube filled with lead chromate is obviated by placing just in front of the boat in the ordinary combustion tube a cartridge of heavy copper wire gauze rolled into the form of a hollow cylinder, 6 or 7. em. long, and filled with pure lead chromate, the ends being closed by wrapping with Cu wire, which, passing also lengthwise through the cartridge, is looped at each end to facilitate removal from the tube. The arrangement has given good results for the determination of C, H, and N in halogen compounds, and would probably also be suitable .for the estimation of C and H in sulphur compounds. W. H. S'

ISSN:0003-2654    

DOI:10.1039/AN906310265b

出版商:RSC    

年代:1906

数据来源: RSC

摘要:

270 THE ANALYST. INORGANIC ANALYSIS. Sampling of Gold Alloys. E. A. Smith. (Clzem. News, 1906, 93, pp. 225, 226.)-Analyses are given proving the importance of carefully removing the coloured surface from gold alloys of all standards before taking the sample for assay, whether by cutting or scraping, the error due to inclusion of the coloured surface amounting with cut samples to as much as 1.27 per cent., and with scraped samples to 13.57 per cent. W. H. S. The Detection of Gold and Platinum in Inorganic Analysis. J. Petersen. (Zeit. aiaal. Chenz., 1906, xliv., 342-344.)-The solution of the metals, which should be slightly acid, is treated with an excess of zinc turnings, which precipitate mercury, silver, lead, bismuth, copper, cadmium, platinum, gold, arsenic (part escapes as arseniuretted hydrogen), antimony, and tin, with some cobalt and nickel, in a granular or spongy form.The contents of the vessel are gently heated for about fifteen minutes and filtered, and the filtrate examined as in the case of the usual filtrate from the hydrogen sulphide precipitation. The precipitate is washed and heated with dilute hydrochloric acid, which dissolves the excess of zinc, the cadmium and tin, and some cobalt. The residue is washed until the washings give no reaction with silver nitrate, and is then boiled with dilute nitric acid. This dissolves the mercury, lead, copper, bismuth, and nickel, leaving a residue of gold, platinum, antimony, and antimonic acid. This residue is washed, dried, and ignited in a porcelain crucible with 1 to 2 parts of ammonium nitrate, and 5 parts of ammoniumTHE ANALYST.271 chloride, with the result that the antimony is volatilized as chloride, and a residue of unaltered gold and platinum obtained. They are dissolved in aqua regia and the solution divided into two parts, one of which is tested for platinum by means of ammonium chloride, and the other for gold by means of sulphurous acid or an alkaline solution of hydrogen peroxide. The filtrates are united, and after evapora- tion of the free acid, the other metals are precipitated by means of hydrogen sulphide. It is stated that platinum and gold were readily detected by this method in 50 C.C. of a solution containing 0.04 per cent. of the former and 0.01 per cent. of the latter, with about 0.5 per cent. of each of the other metals.C. A. M. The Action of Sulphuric Acid on Platinum. M. Quennessen. (Chmz. News, 1906, vol. 93, p. 271.)-It was asserted by Schemer-Kestner that the solution of platinum in sulphuric acid was accelerated by the presence of nitrous products ; but this was denied by Conroy (Journ. SOC. Chem. Ind., xxii., 465), and Delepine (Comptes Rendus, 1905, 866, 1013) found that the addition of nitric acid had no influence on the speed of solution. The author’s experiments have been made with commercial and pure platinum and sulphuric acids of 94 per cent. strength upwards, the heating being done both in vacuo and in an atmosphere of oxygen. I n the case of commercial platinum and 94 per cent. acid, 0.001 gram per square decimetre of metal was dissolved in an hour in vacu.0, whilst 0.124 gram was dissolved in oxygen.With sulphuric acid containing 2 per cent. excess of anhydride pure platinum was dissolved in vacuo to the extent of 0-0265 gram per square decimetre per hour, and sulphurous acid could be detected on opening the tube. The author concludes from these and other experiments that in the case of acid of the ordinary commercial strength it is atmospheric oxygen that acts as the oxidizing agent, whilst with acids of greater concentration the oxygen required is, in the absence of atmospheric oxygen, supplied by the sulphuric anhydride contained in solution in the sulphuric acid. C. A. M. A New Reaction of Niekel. C. Reiehard. (Chem. Ztg., 1906, xxx., 556.)- If anhydrous nickel sulphate is intimately mixed with an equal quantity of methyla- mine hydrochloride (CH,NH,.HCl), and the mixture heated in a small porcelain crucible until white fumes are given oE, a blue colour is developed, which is very delicate at first, but increases in intensity with the heating. On removing the source of heat, the colour is almost immediately changed back to that of the yellow nickel sulphate, but renewed heating will reproduce the blue colour as long as any methylamine hydrochloride is left.As little as 0.0001 gram of nickel will give a decided blue colour. If cobalt nitrate is heated, on the other hand, a blue colour is obtained whether methylamine hydro- chloride is present or not, and this colour is not changed by interrupting the heating. The disappearing of the blue colour consequently appears to be characteristic of nickel.A. G. L. The nitrate and chloride behave in the same way. A New Reaction of Tin. C. Reichard. (Pharm. Centralh., 1906, vol. 47, p. 391 ; through Chem. Ztg., 1906, xxx., Rep., 177.)-Any stannic compound-e.g., stannic chloride-treated with caustic soda and then warmed with finely powdered272 THE ANALYST. uric acid in a porcelain crucible, yields a gray to intense1y:black stain. The reaction is not given by stannous compounds, arsenic, antimony, mercury, copper, lead, bismuth, or cadmium. A. G. L. The Determination of Cadmium. C. Goldschmidt. (Zeit. anal. Chem., 1906, xliv., 344.)-Cadmium is quantitatively precipitated when a solution of one of its salts is boiled in an aluminium vessel in the presence of a trace of chromium nitrate and cobalt nitrate. The precipitation is as complete as that of gold by nickel or of silver by cobalt, and is also successful in the presence of other metals.C. A. M. Complete Analysis of Ferrochrome. G. Dillner. (Jernkontorets Annaler, 1906, vol. 60, p. 253; through Chem Zeit., 1906, xxx., 178.)-Carbon is determined by combustion with lead peroxide i n a current of oxygen. For chromium the sample is heated with sodium peroxide in a nickel crucible ; the melt is taken up in boiling water, and chromium titrated with ferrous sulphate in the filtered and acidified solution. Iron is determined by titration in the insoluble residue from the melt, manganese being determined by Volhard’s method in another similar residue. For silicon the sample is fused with sodium peroxide, and the melt obtained dissolved in hydrochloric acid ; the solution is reduced with alcohol, chromium and iron hydroxides precipitated by ammonia, dissolved in hydrochloric acid, this solution evaporated to dryness, and silica determined as usual.I n the filtrate phosphorus is determined. For sulphur another portion is fused with sodium peroxide. A. G. L. The Detection and Determination of Traces of Iron. A. Mouneyrat. (Comptes Rendus, 1906, cxlii., 1049-1051.)-0n treating 50 C.C. of the very dilute solution of the iron salt with 3 C.C. of ammonia solution (62 grams of NR, per litre) and passing a current of hydrogen sulphide for ten to twelve minutes, a dark green coloration is obtained, the iron apparently being present in a colloidal state.The test is very sensitive, and is capable of detecting 1 part of iron in 800,000. The green colour is destroyed by mineral acids and by many inorganic salts, such as sodium sulphate or chloride in concentrated solution. On the other hand, many organic substances increase the stability of the colloidal condition-e.g., glycerin, glucose, mannite, as well as lactic, tartaric and citric acids, whilst albumin has a particularly marked effect in rendering the reaction more sensitive (1 in 1,000,000). Mercury, lead, silver, chromium, nickel, cobalt, copper, and metals of the alkaline earths, do not give any coloration. Copper, however, interferes with the test for iron, and should be removed by means of hydrogen sulphide. The intensity of the green coloration is proportional to the amount of iron for solutions containing 1 part in 1,000 to 1 in 1,000,000, and a colorimetric determination may be made with the aid of standard solutions of iron.C. A. Ill. Modified Evolution Method for the Determination of Sulphur in Pig- Iron. J. McFarlane and A. W. Gregory. (Cheirz. New, 1906, vol. 93, p. 201.)- The powdered pig-iron is heated to redness with cream of tartar, and the hydrogenTHE ANALYST. 273 sulphide liberated by treating the mixture with hydrochloric acid titrated with standard iodine solution. Five grams of the powdered sample are intimately mixed with about 0.5 gram of cream of tartar, the mixture wrapped in filter-paper, placed in a small covered crucible, and heated to bright redness in a muffle for a quarter of an hour.After cooling, the resulting mass is powdered in a glass mortar and trans- ferred to the evolution flask, where it is treated with boiling HC1 (2 parts acid to 1 part water), the delivery tube from the flask dipping into an ammoniacal solution of cadmium chloride, prepared by dissolving 20 grams of the latter in a litre of water and adding a litre of strong ammonia. For each estimation 25 C.C. of this solution is diluted with about 300 C.C. of water, and placed in a tall beaker. The last traces of hydrogen sulphide are expelled from the flask by boiling, and the liquid containing the cadmium sulphide in suspension is acidified with hydrochloric acid, and the hydrogen sulphide in solution immediately titrated with standard iodine solution, each C.C.of which is equivalent to 0.00025 gram of sulphur, and standardized by means of a steel of known sulphur content. The cream of tartar should be free from sulphur. Results obtained by this process are found to agree very approximately with those found by the “ aqua regia ” method. W. H. S. The Determination of Potassium in Potassium Salts and Artificial Manures. M. Kling and 0. Engels. (Zeit. anal. Chem., 1906, xlv., 315-332.)- The following simpler modification of the Finkener -Neubauer method is recom- mended : 10 grams of the potassium salt are dissolved in 500 C.C. of water, and 25 C.C. of the solution ( = 0.5 gram) mixed with a few drops of hydrochloric acid and the required amount of platinum chloride, and evaporated to dryness in a porcelain basin. The residue is taken up with water and alcohol as in Neubauer’s method, collected in a Neubauer-Gooch crucible, washed with alcohol, and dried by placing the crucible on a moderately hot metal plate.I t is next reduced in a current of coal-gas, the heating being done with a very low flame for the first ten minutes, and finally at a faint red heat for twenty minutes. When the reduction is complete, the crucible is heated-for two minutes over the naked flame of a Tech burner, and, after its contents have been washed about fifteen times with hot water and two or three times with cold 15 per cent. nitric acid, it is placed in a porcelain vessel containing nitric acid, of the same strength, the level of liquid reaching to about three-quarters of the height of the crucible.The vessel is covered with a clock-glass, heated for thirty minutes on the boiling water-bath, and allowed to cool. Finally, the platinum in the crucible is washed with hot water and alcohol, ignited, and weighed, and the weight calcu- lated into the corresponding amount of potassium. The accuracy of the method is shown by the results of test analyses of different potassium salts. I n the case of artificial manures, 20 grams of the sample are shaken with about 800 C.C. of water for thirty minutes in a litre flask, the liquid then made up to the mark and filtered, and the potassium determined in the filtrate. For the potassium 100 C.C. ( = 2 grams) are treated with ammonia and ammonium carbonate in a, 200 C.C. flask, the mixture made up to 200 C.C. and filtered, and 50 C.C.(=0.5 gram) evaporated in a platinum basin. The residue is dried, and, after volatilization of the ammonium salts, ignited until it begins to fuse, and then taken up with hot274 THE ANALYST. water and a little hydrochloric acid. As a rule, solution is complete, but occa- sionally there is a residue, which must be filtered oft‘. The liquid is treated with platinum chloride solution (2 C.C. of a 10 per cent. solution is usually sufficient), and evaporated to dryness, and the potassium determined as above described. I t is shown that the presence of phosphates does not interfere with the accuracy of the results. The paper concludes with a table for calculating the amount of potassium (as K,O) from the weight of platinum obtained from 0.5 gram of the substance.(Factor = 0.48108.) C. A. M. Determination of Sulphur in Pyrites. C. R. Gyzander. (Chem. News, 1906, 93, pp. 213, 214.)-The sulphur is precipitated as BaSO, after reducing the iron to the ferrous state by hydroxylamine hydrochlorate. About 0.2 gram of the finely powdered ore is heated with a mixture of 5 C.C. concentrated HC1, and 15 C.C. concentrated HNO,, evaporated to dryness, another 5 C.C. concentrated HC1 added, and again evaporated. To the residue is added 100 C.C. distilled water, 1 C.C. con- centrated HC1, and 3 C.C. hydroxylamine hydrochlorate solution, containing 1 ounce of the salt in 500 C.C. water, and when reduction is complete the solution is filtered, the filtrate heated almost to boiling, and 10 C.C. of a cold 10 per cent. BaC1, solution added.The BaSO, is then filtered off, washed, dried, and weighed. W. H. S. Determination of Phosphorus and Ash in Coke. J. F. Hoy. (Fourzdry, 1906, vol. 28, p. 155; through Chem. Ztg., 1906, xxx., Rep., 178.)-To determine ash, 1 gram of the finely-powdered coke is mixed to a thin paste with absolute alcohol in a platinum dish of 150 C.C. capacity ; the dish is rotated slowly, so as to distribute the mixture uniformly over the whole of the inside, and the motion continued until the alcohol has evaporated. From five to seven minutes’ heating over a blast-lamp or in a muffle is then sufficient to completely ash the coke. To determine phosphorus, the ash obtained as above is treated with 10 C.C. dilute hydrochloric acid and 29 (? 20) C.C. hydrofluoric acid, and the whole evaporated to dryness.The residue is taken up in 15 C.C. hydrochloric acid ; the solution is trans- ferred to a flask, and treated with ammonia, nitric acid, and molybdic acid, the determination then being finished as usual. A. G. L. Chemieal Methods for the Examination of Coal Briquettes and Bri- quette Pitch. E. J. Constam and R, Rougeot. (GZGckauf, 1906, vol. 42, p. 481 ; through Clzem. Ztg., 1906, xxx., Rep., 178.)-Briquettes should be made from hard coal, but not anthracite, and should contain a certain amount of binding material. The coal used, and the briquettes themselves, should be examined for coke yielded on carbonizing. In Germany, Austria, and Switzerland, Rrlcick’s method is used for this purpose. Broockmann’s ‘6Bochum” test gives results 1 to 3 per cent.lower, but in good accord with the results obtained in gasworks. The Belgian method gives variable results. The American method gives the best results. I t consists in heating 1 gram of the undried coal in a covered platinum crucible weigh- ing 20 to 30 grams in a Bunsen flame 20 cm. high, at a point 6 to 8 cm. above the burner. To determine the coke yielded by the pitch used in making briquettes, theTHE ANALYST, 275 ‘Bochum method is to be preferred. The amount should not exceed 45 per cent. The softening and melting points of the pitch should be noted, and also its behaviour in the molten state. The amount soluble in carbon bisulphide varies from 60.4 to 95 per cent., the average being 79.8 per cent. The calorific value of the pitch should not be below 8,550, and the quantity of hydrogen present should not exceed 5 per cent.TO determine the amount of binding material in the briquettes, the sample should be twice extracted with carbon bisulphide in a Soxhlet for twenty-four hours at a time, the extract being dried for three days over phosphorous pentoxide i?z vacu.0. The amount obtained should not be less than 5 per cent. The ultimate composition of the briquettes should also be determined. The calorific value of the dry briquette should not be less than 7,700, the ash not more than 8 per cent., and the amount of volatile matter not less than 16 per cent. A. G. L. On the Determination of Water-soluble and Total Phosphoric Acid in Superphosphate. K. Rohm. (Chem. Zed., 1906, xxx., 542.) - Water-soizbble Phoqhoric Acid.-A number of determinations were made on three samples to compare the method in which the sample is digested with water for two;hours, with occasional shaking, with that in which it is agitated continuously with water for thirty minutes in a shaking machine, different speeds being also tested. The most constant results are given by the latter method, the speed being about thirty to forty rotations per minute, but digesting the sample without any shaking at all gave results only about 0.2 per cent. too low (with 19 per cent. of water-soluble p@,)* The Sample used should pass through a 2 mm. mesh sieve. Total Phosphoric Acid.-Extraction with nitric acid, with a mixture of nitric and sulphuric acids, and with aqua, regia, gave practically identical results.ExtraC-4 tion with hydrochloric acid, which is never used in practice, gave results about 0.2 per cent. too low. The magnesia precipitate should be allowed to stand twenty- four hours before filtering, or else mechanically stirred for thirty minutes. On allowing it to stand for only two hours, an error of up to 0-22 per cent. of p20, Was found in a number of analyses. A. G. L. On the Determination of Nitric Acid in Water. Paul Drawe. (Chey?a- Zeit., 1906, XXX., 530.)--The author has altered Frerich’s method (Arch. d. phar!)yz-, 1903, 241, 47) as follows : If nitrates have been qualitatively shown to be present, 100 C.C. of the water are evaporated to dryness with an excess of hydrochloric acid. The residue is evaporated several times with water, until every trace of free acid is removed, after which the chlorine in the residue is determined by titration.From the value found the chlorine present in the water itself, plus that due to the alka- linity of the original water, is deducted, and the remainder calculated to nitric acid* The method is said to give good and accurate results. A. G. L.276 THE ANALYST. APPARATUS. A New Weighing-Bottle.-This improved form has many decided advantages over those in use, being easier and more cleanly to work with, and insures greater accuracy in weighing. Also, it may be used for purposes for which the old form was not adapted. The old form has the stopper ground to fit inside the neck ; the new one has the stopper ground to fit like a cap over the neck of the bottle. The advantages claimed are: (1) On tipping out many substances from the old form of bottle, some remains sticking to its lip, and is left exposed to the air when the stopper is replaced, thus absorbing moisture. With the improved stopper the lip remains enclosed, and any substance adhering to it cannot absorb moisture from the air, and so affect the weighing. (2) With the old form, on replacing the stopper after tipping out any substance, it is usually found that some substance remains attached to the inside of the neck, thereby getting ground in between the stopper and the neck, causing the stopper to fit inaccurately, and, if left for some time, this makes the stopper stick so firmly that it is generally broken on trying to remove it. The stopper being outside obviates all this. (3) The stopper, when placed on the bench or table, does not roll about, but lies flat. The old form of stopper rolls about, and is likely to have some substance sticking to it, some of which falling off on to the bench, is lost, and affects the weighing. The new weighing-bottle is generally much cleaner to work with. The bottle may be obtained of Messrs. J. Rerr a d Co., Manchester. (4) Liquids are more easily dealt with. W. J. S.

ISSN:0003-2654    

DOI:10.1039/AN9063100270

出版商:RSC    

年代:1906

数据来源: RSC

摘要:

276 THE ANALYST. PRESERVATIVES IN MILK. The following Circular has been addressed to the various Local Authorities under the Sale of Food and Drugs Acts : LOCAL GOVERNMENT BOARD, WHITEHALL, S.W. July 11, 1906. SIR,--I am directed by the Local Government Board to request the attention of the Council to the subject of the addition of preservatives to milk. A serious objection to the use of preservatives in milk has been pointed out in the report of the Departmental Committee on Preservatives and Colouring Matters in Food, who state that preservatives in milk “ may be relied on to protect those engaged ” in the milk traffic “ against the immediate results of neglect of scrupulous cleanliness. Under the influence of these preservatives milk may be exposed without sensible injury to conditions which otherwise would render it unsaleable.It may remain sweet to taste and smell, and yet have incorporated disease germs of various kinds, whereof the activity may be suspended for a time by the action of the preservative, but may be resumed before the milk is digested.” This Committee, after hearing evidence from milk traders, concluded that the addition of a preservative to milk is not necessary for the purposes of the milk trade, even in hot weather orTHE ANALYST. 277 where the supply of so large a place as London is concerned, and the Committee recommended that no preservatives should be added to milk. In making this recommendation the Committee had special regard to evidence received as to two classes of preservative substances which, under various names, are frequently used as preservatives in milk-viz.: (1) Formalin (a 40 per cent. solution of formic aldehyde) and other preparations of formic aldehyde ; and (2) boron preservatives (boric acid, borax, or mixtures of boric acid and borax). The Committee considered that the addition to milk of formalin or preparations of formdin, even when the amount which could be detected was minute, was objectionable, on account of the alterations effected by formalin in the character of certain of the constituents of milk and of its ability to interfere directly with digestive processes. Although in the view of the Committee boron preservatives might reasonably be employed in the case of certain foods, within defined limits and subject to a declaration as to their presence and amount, the Committee recomrnended their exclusion from milk altogether ; partly for the reasons above indicated, and partly also in consideration of the immense importance of pure milk for the nutrition of infants, invalids, and convalescents, and of the comparatively large quantity of milk which may be taken, particularly by children, in comparison with the other foods in question.Moreover, the Committee had evidence " pointing to an injurious effect of boracized milk upon the health of very young children." Since the report of the Committee was made, the Board have from time to time had before them further evidence on the subject, and this supports the conclusions of the Committee not only as to the objections to the use of preservatives on the ground of public health, but also as to the ability of milk traders to conduct their business without use of preservatives.Thus in certain boroughs in London and elsewhere in which milk samples are systematically tested for preservatives, the presence of preservatives in milk at any time of the year has been found to be exceptional ; and there is evidence to show that a very large number of milk vendors conduct their business without the use of these substances, even where the milk comes long distances by rail. I n some districts action under the Sale of Food and Drugs Acts has been frequently and successfully taken in order to bring about the disuse of preservatives in milk. Proceedings instituted against vendors of milk containing preservatives have usually been taken under Section 6 of the Sale of Food and Drugs Act, 1875.Conviction has followed, it being held that when the purchaser who asks for milk is supplied with milk plus a preservative, he does not receive an article of the nature, substance, and quality demanded, and is prejudiced thereby. The Board are of opinion that action under the Sale of Food and Drugs Acts in regard to preservatives in milk is desirable, and that this subject deserves attention from all authorities in England and Wales charged with the execution of these Acts. I n this connection the following suggestions are made for adoption by the Council where a similar procedure is not already followed : 1. Informatio3 from Public Analysts. The Board suggest that Public Analysts should be requested- (a) To record in their quarterly reports how many milk samples have been examined during the quarter with a view to ascertaining the presence of substances commonly in use as preservatives, and with what result ; and to draw the attention of the Council to instances where the use of preservatives in milk other than boron preservatives and formalin have come under notice.( b ) To report; on completion of analysis, the facts as to samples of milk which have been found to contain any added preservative.278 THE ANALYST, 2. Administrative Action where Preservatives in Milk are reported. The Board would suggest that the Council should notify to milk traders, by circular or otherwise, that action will be taken under the Sale of Food and Drugs Acts in instances where preservatives are reported in milk.Subject to this being done, and to exceptional cases of the kind referred to under the heading numbered 3 below, the Board consider that when the presence of any added preservative is reported in a sample of milk taken in accordance with the provisions of the Sale of Food and Drugs Acts, the case should in ordinary circumstances be regarded as one for the institution of proceedings under those Acts. 3. Declaration and Notices. The Board think it desirable to draw attention to cases in which the vendor of the milk, with the object of escaping liability under Section 6 of the Sale of Food and Drugs Act, 1875, declares to the purchaser by means of a notice, label, or otherwise, that he does not sell " milk " as such, or that its quality in regard to preservatives or other constituents is not guaranteed, or that it contains some added preservative.The Board would suggest the desirability of frequent sampling in cases where " milk " is sold subject to declarations of the kind, with a view to ascertaining the condition of such milk in regard to preservatives. The nature of the declaration made should in all cases be carefully recorded by the officer taking the sample, and should also be reported to the analyst when the sample is transmitted for analysis. Where preservatives are reported in milk thus sold, the question will arise whether, in view of the nature and quantity of the preservatives added, it can be considered that the article has been rendered injurious to health, or that the purchaser has been prejudiced, to an extent which would justify the institution of proceedings under Section 3 or Section 6 of the Sale of Food and Drugs Act, 1875, notwithstanding the declaration made at the time of purchase, This question is not without difficulty in view of the general objection t o the employment of any preservatives in milk referred to above.As regards formalin and boron preservatives, however, the Board are advised that the presence in milk of formalin to an amount which is ascertained by examination within three days of coZZecting the sanaple to exceed 1 part in 40,000 (1 part in 100,000 of formic aldehyde) raises a strong presumption that the article has been rendered injurious to health, and that the purchaser has been prejudiced in the above sense ; and also that similar presumption is raised where boron preservatives are present in milk to an amount exceeding 40 grains of boric acid per gallon. I t appears desirable that the addition of preservatives to skim milk, separated milk, and condensed milk should be watched and controlled on similar lines. Additional copies of this Circular are enclosed for transmission to the Public Analyst, and for use by executive officers under the Sale of Food and Drugs Acts. The Circular will be placed on sale, and copies can then be obtained from Messrs. Wyman and Sons, Limited, 109, Fetter Lane, Fleet Street, London, E.C., either directly or through any bookseller. I am, Sir, Your obedient servant, S. B. PROWS, Secretary.

ISSN:0003-2654    

DOI:10.1039/AN9063100276

出版商:RSC    

年代:1906

数据来源: RSC

摘要:

THE ANALYST. 279 REVIEWS. STUDIES ON IMMUNITY. By Professor PAUL EHRLICH and his Collaborators. (New York : John Wiley and Sons. Ehrlich’s studies on immunity have acquired a world-wide reputation, and all investigators in this important field of study will welcome an English translation of the work of himself and his collaborators. I n his preface the author points out that Behring’s great discovery of antitoxin opens new paths for research, first in the direction of the production of individual curative sera, and, secondly, in seeking a deeper insight into the nature of immunity phenomena. Ehrlich’s theories are developed on the basis of chemical conceptions, and he shows that the significance of morphological structure is far less than that of the chemistry involved. By a comparison with the mechanical conditions and suitable apparatus that aid, but are not absolutely necessary to a chemical process that depends essentially on the constituents involved, so in biology the morphological arrangement of the organs and cells is not the essential feature.This is rather to be sought for in chemical differences of the constituents. The products of bacteria, as well as the artificially-produced bacteriolysins and most of the ferments, according to the author, produce their effects by the presence of two active groups in the molecule, one of these uniting with the substance to be acted upon, whilst the other produces the characteristic effect. This theory is bound to affect the study of vital phenomena, especially intracellular metabolism and other physiological problems, such as those of secretion, heredity, etc.The book comprises forty-one chapters by various investigators on the subject of immunity, including many by Ehrlich himself. One of these is of special interest from the chemical standpoint, consisting as it does of a discussion of the relations existing between chemical constitution, distribu- tion, and pharmacological action. The author here ahows that at the present time the chemical aspect constitutes the axis about which the most important views in medicine turn, and that the two poles are the synthetic construction of new therst- peutic agents on the one hand, and the discovery of specific therapeutic products of living cells on the other. He also enumerates the conclusions that can be drawn from the study of the large number of medicaments of therapeutic importance. I n this synopsis the fact is emphasized that the antipyretic power of antipyretics is destroyed by the intro- duction of salt-forming acid radicals, such as S03H and COOH, and cites as an illustration of this acetanilido-acetic acid (C,H5N(COCH,)CH2COOH), and acetanilin sulphonic acid (C6H,NH.C0.CIE12.S03H), which are inert in this respect. Ehrlich also mentions that the presence of the ethyl group in certain disulphons -for example, sulphonal [(CH,),C(S02C2H,),] and trional [CH,C,H,C (SO 2C2H,),], as shown by Baumann-gives to these substances their hypnotic property, and that the latter increases with the number of these groups. Another interesting chapter is that by Dr.Preston Kyes and Dr. Hans Sachs on the substances which activate cobra venom. Translated by Dr. CHARLES BOLDUAN. London : Chapman and Hall, 1906. Pp. 586. Price 25s. 64. net.)280 THE ANALYST. The book is well arranged, and should prove of great interest and value to all students and workers in the important subjects of immunity and vital phenomena. OFFICIAL CHEMICAL APPOINTMENTS. By R. B. PILCHER. (London : Institute of Whilst the clerical, legal, and medical professions have been long since well supplied with copious directories, giving, amongst other things, lists of appointments held by members of each respective profession, no approach to such convenient works of reference has been hitherto compiled for the chemical profession. I n order to fill up this void, Mr.R. B. Pilcher, the able Registrar of the Institute of Chemistry, has, under the direction of the Council of that body and under the supervision of its Pro- ceedings Committee, undertaken the compilation of such a work. The list of official appointments is in two divisions, the former embracing the holders of appointments in Great Britain and Ireland, the latter of those in our colonies ; that of appointments held by Public Analysts, which was published some months since, has also been incorporated with the work. I n order to be as comprehensive as possible, appoint- ments in connection with agriculture, metallurgy, assaying, and other branches of work where chemical knowledge is required are mentioned. I n many instances particulars are given as to the Acts under which appointments are made, as well as the regulations and conditions of such appointments.The work also contains a large quantity of useful miscellaneous information on many subjects. Mr. Pilcher is to be congratulated on the excellent manner in which he has per- formed his arduous task ; he has succeeded in producing a very useful and highly interesting book for members of the profession to whom it relates, as well as to many outside that profession. * + l 3 4 + @ * Chemistry. Price 2s. net ; post free, 2s. 3d.) W. J. S. INSTITUTE OF CHEMISTRY OF GREAT BRITAIN AND IRELAND. PASS LIST OF THE JULY EXAMINATIONS. OF fourteen candidates who entered for the Intermediate Examination, the following nine passed: L. C. W. Bonacina, W. R. S. Ladell, D. J. Law, W. M. Seaber, B.Sc. (Lond.), P. Stutfield, J. M. Weir, MA., B.Sc. (St. Andrews), W. A. Whatmough, J. MI. Wilkie, B.Sc. (Lond.), and C. H. Wright, B.A. (Cantab.). I n the Final Examination for the Associateship (A.I.C.), of three examined in the branch of Mineral Chemistry, two passed : J. W. Agnew and I. M. Heilbron. Of three in the branch of Organic Chemistry, two passed: R. Le Rossignol, B.Sc. (Lond.), and G. W. Monier-Williams, M.A. (Oxon.), Ph.D. (Freiburg). And of eight who entered in the branch of the Analysis of Food and Drugs and of Water, including an Examination in Therapeutics, Pharmacology, and Microscopy, the following six passed: J. G Annan, B.Sc. (Lond.), C. T. Bennett, B.Sc. (Lond.), G. W. Glen, F. W. Harris, E. H. Merritt, B.Sc. (Load.), and F. Tattersfield. The Examiners in Chemistry were Mr. W. W. Fisher, M.A. (Oxon.), F.I.C., and Dr. G. G. Hender- son, M.A. (Glasgow), F.I.C. The Examination in Therapeutics, Pharmacology, and Microscopy was conducted by Dr. F. Gowland Hopkins, M.A. (Cantab.), F.R.S., F.I.C.

ISSN:0003-2654    

DOI:10.1039/AN9063100279

出版商:RSC    

年代:1906

数据来源: RSC