摘要:

THE ANALYST, NOVEMBER, 1884. 6; Ir, very loviizg remembrance of GEORGE WILLIAM WIGNER, F.I.C., P.C.S. (eldest son of ths .Rev. J. T. Vigner), of Tickham Boa6, Broclcley, 8.Z.? who, just niae rizortths after hi8 loved Wgo's decease, and after zoeeh of severe sufering, peacs- ficl'ly passed away, October 17, 1884, aged 42 year$." SUCH were the words of the card announcing to the public analysts of Great Britttin the sad news of the decease of the first President of our Society who has died during the term of offioe. When an old connection is thus rudely severed and a literary and official union of years is terniinated, it is a sad and difficult task to sit down and announce the bare fact without attempting to make our readers familiar with the sincere private relations and many virtues of the departed one as a husband, a father, a chemist, and a friend, but such matters must be sup- pressed when performing a public duty, and me will, therefore, only speak of the deceased in his official capacity.To the buxiness talents and organising power of George William Wigner the Society of Public Analysts owes its existence, for it was his devoted zeal and personal labour that carried the young babe safely through the perils of infancy and the temptations of adolescence ; and when, having safely brought it to years of discretion, ho resigned the Secretaryship and accepted the Presidency, all hoped that he would remain with us to see the fruits of his work in bringing together the public analysts in permanent bonds of unity, and of encouraging and fostering through this Journal a new branch of science even now in its infancy. But it very often happens that the cup of happiness is dashed unexpectedly from om lips, and just at the moment when many of the leading spirits of our Society mere venti- lating among tltemselves the idea of marking his untiring zeal by offering him the exceptional honour of an additional year of Presidency, he is gone, and me are left to bow to the decision, and to reflect that he is, after all, perhaps, in a happier state than those still remaining amidst the trials and sorrows of life I The funeral took plye at Brockley Cemetery on the 22nd inst.where a number of public analysts reverently assisted the relatives in laying their respected friend to rest, surrounded by one of the largest assemblies that we have ever soen at a private interment. As we took our last lingering look on that solemn occasion, the words of the poet Gray came before our minds, and in shadowing forth our present painful task we felt that we should : - '' No farther seek his merits to disclose, Or draw his frailties from their dread abode. Where they dike in trembling hopes repose The bosom of his Father and his God."

ISSN:0003-2654    

DOI:10.1039/AN8840900193

出版商:RSC    

年代:1884

数据来源: RSC

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194 THE ANALYST. NOTES ON THE E8TIMATION OF LEAD IN BBATED WATERS. BY ALFRED H. ALLEN. I RECEXTLY received from an inspector under the Sale of Food and Drugs Act, a sample of lemonade, which I certified to contain 1Q grain of lead per gallon. The estiniation was made colorimetrically with sulphuretted hydrogen, and the presonce of load was confirmed by chromate of potassium, which gave an immediate turbidity in the uncon- centrated sample. In consequence of my certificate, the vendor was snmmoned before the magistrates at Otley Petty Sessions, when his solicitor produced a certificate from Mr. F. Riinmington, of Bradford, stating that the sample contained *05 grain of lead per gallon. I n consequence of the discrepancy between our certificates, the remaining portiou of the sample was refemeci to Somerset House, whence, in due course, a certificate was received stating that the sample contained 1/55 grain of lead in 10 oz., and that this proportion mas within the limits of accidental impurity.Calculated on the gallon, the amount of lead found by Somermt Rouse is 0.30 grain per gallon, but, of course, the Bench did not understancl this,-and the defence took care not to tell them--while I, the imfortunate analyst, had not even been infoimed that my certificate was in dispute. The result was that the case was dismissed, together with another in which the facts wei’e similar, but the magistrates decided to reserve the question of costs till they leaimeci whether any explanation was forthcoming. Thus, at len@h, 9: have heaid of the case, and have had an opportunity of calling attention in writing to the following facts :- The samples were never diiided at all.Three closed bottles of eachmere 1lurchasecl, sealed by the inspector, and duly distributed between the vendor, the analyst, and himself. It is evident that the contents of the three bottles should have been mixed (in a jug), and then divided, if so required by the defendant. Seeing that are-examination of the remaining portions of my samples has proved the substantial accuracy of my certificates, it is clear that there W I L ~ no accidental inistake or transposition, and, as the estimation of lead in water is too simple a matter for an error of chemistry to occur, I prosume that the mnountR of lead found by Mr. XCirnmington, the Somerset House chemists, and myself, really reprefiented the proportions of metal present in the various2HE ANALY8T.195 -- bottles examined by us. If this be the case, it is certainly rather stai4ling to find that bottles of arated water, from the same manufactory, and of presumably nearly contem- poraneous manufaature, should be apt to contain amounts of lead varying so much as the figurks of Mr. Rimmington and myself show, but the probable cause of the vayiation in the amount of lead will be evideiit to the readers of the ANALPST. If we assume the 0.3 grain of lead per gasLon found by the Somerset Homse chemists in their poi%ion of one of the samples to represent the general extent of the contamination by lead, it is clear that the case was not one to be pooh-poohed or dismissed, for, although 0-3 grain per galloii may be within the limits of accidental impurity, people w i l l gene~ally object to be poisoned, even accidentally.Another point worthy of notice in the examination of mated waters for lead is the tendency of the contents of a bottle to become contaminated from contact with the leaden alloy which foims part of the stopper aiwmgement in a. certain description of patent bottle. 111 a recent instance I found 0. I7 grn. of lead in a sample of lemonade analysed a few days after it was received, but after standing some three weeks, with the leaden portion of the stopper immersed, the proportion of lead had increased to 3-36 grains of lead per gallon. In all cases in which I test for lead in mratccl waters I a531 in the habit of eonfilm- ing the result by the chromate test.'When carefully managed, chromate of potassium. aill indicate any proportion of lead greater than one-third of a grain per gallon, without it being necessai'y to concentrate the water. The sample should be placed in a Nesaler cylinder and a drop of potassium cboniate solution added, in snch a manner that the yellow solution gradually sinks through the clear and colourlcss liquid. The faintest cloud of lead chomate can thus be recognised. Addition of acetic acid seriously mars the delicacy of the test. I n testing =rated waters for load with sulphurstted hycbogen, the possible presence of tin and coppel* must not be lost sight of. Copper, if present, may at once be recognised by the ferrocyanide reaction, but traces of tin are not readily identified.The plan I have found best is to precipitate 200 C.C. of the water with sulphuretted hydrogen and clissolve the precipitate in strong hydrochloric acid. When the sulphwetted hydrogen is expelled, the solution is diluted somewhat, and boiled with metallic iron to insure that the tin exists in a stannous condition. The liquid is then decanted from the undissolved iron and tested with mercuric cliloi*ide, when any formation of a dky-looking cloud of niercurous chloride will bc readily recognised. Although not closely connected with the detection of metals in arated. drinks, I may take this opportu&y of calling attention to the fact that the ordinary teat for zinc, with an alkaliiie sulphide, is far fro111 delicate. A much inore satisfactory test is one which I described many years ago iu the Chen&,nZ Xws, Vol. ~XXLII,, page 290, but it has never €ound its way into the text books. The solution to be tested for zinc is rendered ammo- uiacal, heated to boiling, aiid potassiuui fcrrocyanicle added, when a white precipitate be produced if the mei'cst trace of zinc b~ present,

ISSN:0003-2654    

DOI:10.1039/AN884090194b

出版商:RSC    

年代:1884

数据来源: RSC

摘要:

196 THE ANALYST. MONTHLY RECORD OF ANALYTICAL RESEARCHES INTO FOOD. AT the meeting of the American Association for the advancement of Science, Prof. A. R. Leeds reported that he found the composition of human milk, on using every precaution, to be : albuminoids varying from -5 to 4.25 per cent., lactose from 4.1 to 7.8 per cent., and fat from 1.7 to 7.6 per cent. The appearance and specific gravity of human milk, according to the same authority, never give any real index of its composition. At the ~ a m e meeting Professor Atwater read a paper on the chemistry of fish. Flounder is the least nutritive of fishes ; while the salmon, when fat, is the most nutritive. Oysters have least nutritive matter among the invertebrates ; and northern oysters are more nutritive than those from the south, The flesh of fish contains less fat and more water than that of vertebrates.Digestive ferments act upon the flesh of fish in the same may as upon that of the vertebrates, about ninety-eight per cent of the albuminoids being digested in both cases. As ordinarily found, fish gives from five to twenty per cent. of edible matter. I n the last Zeitschqtfur AtaalzJtische Chencie, J. Uffelman makes an advance upon Fuch’s idea as to the presence of nitrates in milk, proving the addition of impurewater, and he has further amplified the matter so as to take into consideration the presence of ammonia and nitrous acid. He adds diluted acetic acid to 350 C.C. of milk until the caaeine is entirely thrown down ; 100 C.C. of the filtrate are then mixed with three drops of hydrochloric acid, boiled up, allowed to cool, and filtered.Of this new filtrate 50 C.C. are rendered faintly alkaline with pure potassium hydrate, filtered, clistilled, and the dis- tillate is tested with Nessler’s reagent. To the remaining 50 C.C. are Rdded sodium hydrate and carbonate, the mixture is filtered, and tested with Nessler’s reagent. The residue-of the liquid filtered from the acetic acid precipitate is boiled and filtered. 30 c.c are tested with meta-phenylen-diamine, and another 30 c.c, with zinc-iodide-starch paste for nitrous acid. The remainder is utilised for detecting nitrates by means of diphenyl- amine. A little ci*ystalline diphenylamine is dissolved in a white capsule in about 1.5 c. C. of pure sulphuric acid (full strength) and three t o four drops of the milk atrate are added.I n presence of much nitric acid there is foirned almost immediately a blue zone, which quickly extends. If there is little nitric acid the colour appears only after some time. I f the blue colour does not appear, the experiment is successively repeated with portions of the milk-filtrate, concentrated respectively to one-third, one-seventh, and one- tenth of the original volume. Neither ammonia, nitric nor nitrous acid, is ppesent in normal milk, but all t h e e may be introduced by sophistication with inipure well-watep, In the same volume M. Vitali points out that when funel oil (amylic alcohol) hae been separated from spirit by Betelli’a method of shaking up with chloroform, its presence in the residue may be proved as follows !-If the reaidue Buepected to be arnylie alcoholTHE ANALYST.197 be poured upon sulphuric acid, and then cautiously stirred with a glass rod, a play of colours is produced, commencing with dMy red and passing through violet to azure blue, and lastly to green. The addition of a fern drops of ether makes the colours more brilliant. rChe following is a description of a water bath designed to keep the water at a constant level by Dr. E. Mascarenas y Hernandes, in La ATatzcre :- The reseivoir for water is a bottle tightly stoppered and through the stopper of which two glass tubes pass bent twice at right angles, one terminating just below the stopper, and having its outer limb ending at the exact level at which the water in the bath is to be kept, while the other tube extends to the bottom oi the reservoir with one limb, and with the other to some distancedown the neck of the water- bath.As soon as the siphon has been started, the water will flow from the reservoir until the end of the shorter tube becomes closed by the water, when the flow mill cease, to begin afresh L~EI soon as the level sinks. In April last an attempt was made by H. Rabourdin, to estimate the amount of adulteration in commercial peppers, by olive stones and husks, and other similar hard bodies. It was published in the French Jourfial de Phamaoz'e, and has been hitherto passed over without much notice, but we have found it very useful as an aid in the microscopic examination of pepper, and to a certain extent fairly quantitative for other hard adulterants besides those named.It is as follows :- A gramme of the sample is boiled continuously €or an hour in 100 grammes dis- tilled water and 4 grammes sulphuric acid, adding more water from time to time to make up for the loss by evaporation. The flask must be supported by the neck or it will be fractured by bumping. After boiling for an hour the liquid is allowed to cool, and poured upon a plain double filter which has been previously well dried and tared. m e n the pepper contains olive-kernels they fall to the bottom of the flask, and when the liquid is poured upon the filter they are found upon the sides of the flask in reddish fragments, more or less plentiful. This character already is decisive, since pure pepper never gives these dense, reddish fragments.The flask is repeatedly rinsed out, and the iilter with the residue is perfectly washedwith boiling distilled water. It is then dried and weighed very carefully. The weight of this total residue forms the coe@cimt of the pepper, This value is vayiable for every kind of pepper, but for all pure kinds within ve~y naprow limits, and is strikingly increased when the pepper is adulterated with kernels or shella. The average valtte for pure peppers of commerce, 0.35. On the other hand, that of tho olivebkemels is on the average 0.745, and that of the husks or shells 0.70.--_THE ANALYST. TEE DETERMINATION OF TEE ALBEMINOIDS IN HUMAN MILK E. PPEIFFER. (Communicated by the Author to the Zeitschrift f. Physiol. Chemie, 8.259.) THE author's researches deal, firstly, with the precipitation of caseine by acids ; and, secondly, with the determination of the total albuminoids, according to the methods hitherto proposed.I- 198 As regards the first point, the author shows that in the precipitation of caseine; according to his method (viz., that of digestion for 10-15 minutes at 50-55"R. with dilute hydrochloric acid), other acids, diluted to the requisite strength, may be substituted for the hydrochloric acid. Thus, lactic acid (1 c. c, pure acid of sp. g. 1,0065 to 40 c. c. H,O), acetic acid (2 c. c. concentrated acid to 100 c. c. H,O), and sulphuric acid (2 c. c. conc. acid to 100 c. c. H20) produce, when added in drops, a pronounced coagulation. Dilute phosphoric and nitric acids do not give such good results.With the right strength of acid the coagulation takes place at a temperature as low as 30-40°R., which proves that a high temperature is not essential to, but only hastens the coagula- tion. The precipitation is best when the acidulated inilk is placed in water at a temperature of 25-30°R., and then slowly warmed to 45OR. The author then proceeds to compare (as regaids the results obtained) his ( ( hyilro- chloric acid method" (Zeitsch fur Anal. Chem. 22, 14) for the determination of tho total albuminoids, nith the method in which they are precipitated by tannin, and the one in which an equal volume of alcohol is used. Following the directions given by Biedert for the tannin method, the author used n 10 pel* cent. aqueous solution of tannin, of which 2-4 c.c. were found necessary for 10 grms. of milk. Sufficient tannic acid having been used, the precipitate, containing the total aIbuminoids and fats, was easily Btered and mashed xithout loss. It appears, howeveie, that its weight, after the renioval of the fats, cannot be used for the calculation of the total albumiiioids, as it contains variable quantities of tannic acid. Besides this, the filter paper is liable to become very weak, especially when much tannin is used, and, on drying, to fall to pieces. The author finds more serviceable the method depending upon the precipitatiou of the albuminoids by alcohol, more especially because it allows of an approximately separate determination of the caseine and of the albumen. The greater part of the albuminoids, which the author regards as essentially caseine, is precipitated by adding an equal volume of cold absolute alcohol.Care must be taken not to add it in too large a quantity, as the precipitate is not thereby rendered more coniplete, whereas, on the other. hand, a larger quantity of butter-fat is dissolved, which necessitates afterwards a separate fat deteimination in the filtrate. For the same reason, the autlior reconmellds washing the precipitate with an alcoholic solution, coutainiiig equal volumes of absolute alcohol and wateii, the washings, however, should not exceed the volunie of milk taken. The filtrate, together with the washings, is, after the addition of a little water, evapo- rated until no more alcohol remailis ; it is then boiled, and the precipitate, thus pz*oducsd,THB ANALYST.199 collected upon the filter, dried, and weighed. I n one part of the filtrate, the sugar may be estimated by any of the ordinary methods, while the albuminous residue ’’ can be determined by precipitation with tannin. Analyses of the same milk, carried on simultaneously, on the one hand by the alcohol, and on the other by hydi*ochloiic acid method, did not, however, completely agree. The results are mostly higher for both the caseine and the albumen, with the hydro- ohloric acid method, Le., the sum of the caseine and the albumen is generally greater than in the &oh01 method, BO that a less quantity of the ‘( albuminous residue ” remains to be precipitated by tannin. For this reason the author prefers his method. The author adds to hia former communications, the observation that he has found the temperature S0-55Ql%.the best for the coagulation of the caseine. I?. H. H. Bonn, 21st October, 1884. f)r. Henry LeffrYrann has published a series of analyaes of butter, which we sum- marise from his article in the Chmical News, chiefly because they axe performed by a process not uaually employed by British analysts. Dr. Lef€mann uses the method of Koettatorfer in preference to any other, Viz., ascertaining the quantity of real potassium hydrate required to saponify the fat, and he also takes advantage of the odour of butyric ether given off during limited sapon2fication with alcoholic soda, to prove the existence of butter at all. His results are expressed in terms of the amount of standard acid to which one gramme of the fat is equivalent in action on alkali. Divesting his table of unimportant particulars, we have the facts that :-- Genuine butters took from 5.5 to 6 9 acid, and gave a powerful ethereal odour. Doubtful ,, ,, ,, 5.0 to5.1 t P 9. feeble ?P >t 4‘Bogu~” ,) ,, ,, 4.3 to4.9 ,? ?, 90 ?? ?? Although there is nothing very novel in the above information, still we put it on record, as every faot tending to throw any light on food analysis, should be recorded in our aohmns.

ISSN:0003-2654    

DOI:10.1039/AN8840900196

出版商:RSC    

年代:1884

数据来源: RSC

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THE ANALYST. 199 MONTELY RECORD OF ANALYTICAL REBEABCHES INTO DRUGS. AT the last meeting of the American Pharmaceutical Association, Professor Prederick B. Power gave a very interesting paper upon Hydrastine, the active principle of .Eyha;stis ca;nadensis, of the analytical and descriptive portion of which the following is an abstract:- The crystals of hydrastine, yhich apparently belong to the orf&o-rhombic system, are anhydrous, and when pu~e, perfeotly colourless and very brilliant. They fuse at 132O C. (Mahla states 135' 0.) to a light amber-colomed liquid. When heated on platinum foil they decompose with the evolution of empyreumatic inflammable vapours, reminding, asMahla had previously observed, somewhat of carbolic acid, and leaxing a large amount of ash, which burns slowly away at a red heat.200 THE ANALYST, Hydrastine iiJ insoluble in water and in petroleum benzin, these liquids leaving, after prolonged contact with the alkaloid, no perceptible residue upon evaporation, and the aqueous liquid is not affected by potassio-mercuric iodide ; it is soluble, however, in dilute acids and in chloroform (in 1.75 parts), benzol (15.70 parts), ether (83.46 p.), and alcohol (120.27 p.), and, of course, much more freely soluble in these liquids when hot.Its specific rotary power is (a) D = - 170'. The crystals of hydrastine are affected in the following manner by re-agents :-- Concentrated sulphuric acid produces a yellow colour, which, in contact with a crystal of potassium bi-chromate, becomes brown. Concentrated sulphuric acid, on warming, produces a bright-rod colour.Concentrated nitric acid produces, in the cold, a yellow colour, changing to reddigh-yellow. Concentrated hydrochloric acid givea no colouration, either in the cold or upon warming. Concentrated sulphuric acid and ammonium molybdate gives an olive-green colour, which appears to be its most characteristic test. The solution of the hydrochlorate is affected as follows by re-agents :- Ammonia water and the fixed alkalies give a white curdy precipitate, spa6ngly soluble in excess ; potassium, iodide, potassio-mercuric iodicb, potassium ferrocyanide, potassium sulpho-cyanide, mercuric chloride, and tannic acid produce white precipitates ; iodine in potassium iodide, a light-brown precipitate ; potassium bichromate, a yellow precipitate ; picric acid, a bright yellow precipitate ; platinic chloride, an orange- yellow precipitate ; awic ohloride, a deep yellowish-red precipitate.At the same meeting, Nr. W. Bartlett contrasted and criticised the methods for the estimation of Morphia in Opiiinz, official, in Great Britain, Germany, and America, much to the advantage of the last-named. This process, as some of oiir readers may not be aware, consists essentially in ikbbing seven grammes of opium with three grammw of slaked lime and 20 C.C. oP water, until uniformly mixed, then adding 50 C.C. more water, and stirring occasionally for half an hour, and then filtering off 50 C.C. into a hpperecl bottle (= 5 grins. opium). This liquid is then mixed with 5 C.C. alcohol and 25 C.C. ether a i d shaken, and three grammes of powdered ammo- nium cloride having been added, the whole is again shaken and set aside for 12 hours.The ethereal layer is decanted upon a pair of counterbalanced filters, which are then rinsed with 15 C.C. o€ ether, and finally the crystals of morphine are col- lected upon the filters, air dried, washed with 10 C.C. of water, and dried between 55" and 60" C. Mr. Baptlett's experience of the practical working is as follows :- In using the U. S. P. process, I found that certain details which could not be properly put into the Phamnacopooia, mere quite useful in carrying out its requirements. Thus, the freshly-slaked lime should be in the powdered form. This can be done by using lime, three parts, and water one part. The quantity of slaked lime directed to be used is intended to be in excess, so that if a little more is used there will be no harmTHE ANALYST.201 done. Hence, it can be weighed in a larger balance, if it is more convenient to do so. Then the ammonium chlorido is also in excess, and can also be weighed on a large balance, cam being taken, however, to have at least tlhe fitlZ quantity. The commercial ammonium chloride, in the form of crystal, was carefully powdered in a mortar each time, as the powdered ammonium chloride of the market should not be relied on €or purity. Then the filter should be wet with ether before decanting the ethereal layer upon it, for it is the ether that we wish to pass through first, and thus hasten the prbcess. A fine glass rod was used to decant upon the filtei*.I n decanting the ethereal layer, there is no absolute necessity for being particular to decant only the ethereal layer, for at least one-half of the other liquid will bo carried along with it in any event, I foupd it con- venient in washing the crystals with ether, to do so with ~ l t two C.C. pipette. After the crystals have been washed with ether, they need to be dried in the air only long enough to get rid of the ether, perhaps an hour. This is necessary, in order that the rest of the liquid, when added, will filter readily. I havo spoken of these points rather more in detail than I otherwise should, fo? the benefit of those who may have met with these difficulties, and have not clearly seen their way out of them. The results of the three samples assayed by the U.S. P. process are as follows : No. 1, 12.50 per cent. of morphine. ? ? 2, 12'48 1? I , ) > ?, 9 9 3, 13.40- 9 , 9 , 7, ?, The crystals were quite well defined, and quite light coloured. Sample of opium No. 1 was quite dark coloured ; samples Nos. 2 mid 3 were quite light coloured ; which shows that the colour of the opium is no guide to its morphine strength ; fand, indeed, 5: have found that the physical appearances of powdered opium, as a rule, give no clue t o its morphine value. The result of the same three samples assayed by the process of the German Phar- macopcleia are as follows : 8.50 per cent. of morphine. No. 1, 7 7 2, 10.fio 3 ) ,, ? Y > Y , j 3, 9'25 ?, 9 ) ?? > ? The crystals were quite light coloured, and somewhat larger than those produced by the U.8. .P. process, !Phis proeess is somewhat tedious, the liquids all being re- quired to be weighed. The crystals of morphine were dried at between 70" C.' and 80" C. till they ceased to lose weight, rather than at 100" C., in order to make sure that none of the morphine be lost. This process claims ten per cent. of morphine. The results of the same three 'samples asRayed by the process of the British Bharmacopceia me as follows : No, 1, $112 per cent. of morphine. 11 3, 8-25 9 7 9 ) 9 , 7, 9 ) 8, 3-43 7 1 ? > $ 7 , I202 TPEEE ANALYST. Doubtless the new revision of the British Phaimacopmia will supply a much better method of assay. The present one claims from 6 per cent. to 8 per cent. of morphine. The morphine obtained in each case was shaken with one hundred parts of lime-water, and in no case was it completely dissolved, but in each case vei'y nearly so, and all to the same extent.The morphine of the U. 8. P. and German Pharmacopceizt was quite light in colour, the 17. S. P. being quite as light as the German, and the British was quite dark. It w i l l be seen that the U. S. P. process calls for at least 12 per cent. of morphine, that the German calls for 10 per cent. morphine, and that the British calls for at least 6 per cent. of morphine, and that by actual experiment the U. S. P. process gave the largest yield, the German a much smaller yield, and the British theleast of all. That the moi.hine in each case dissolved to the aaine extent in lime-water, and that the morphine obtained by the U. S. P. process was much lighter coloured than the British, and quite as light-coloured as the Geriiian, a d gave a far larger yield than either of the other processes. ,The only inference that can be cham from these results is that the present U. S. P. process is by far the most definite as to detail, yields by far the most morphine, and hence exhausts the opium more thoroughly than any of the other processes.

ISSN:0003-2654    

DOI:10.1039/AN8840900199

出版商:RSC    

年代:1884

数据来源: RSC

摘要:

202 TPEEE ANALYST. MONTBLY RECORD OX GENERAL RESEARCHES IN ANALYTICAL CEUZMIBTRY. THE past few weeks have been very productive of research-work in Analytical Chemirs- try ; in Geiman laboratories several new methods and interesting separations have been worked out ; and of these Pi*esenitw’ laboratory at Wiesbaden takes, of course, the lend. Among other resemches which have lately been brought to completion in this laboratory is a new method for the determination o f arsenic. THE DETERMINATION OF ARSENIC*-BP CIARL HOLTHOQ. Difficulties have always attended the estimation of Arsenic, due pmtly to the volatility of ai*senious chloride, in the presence of concentrated hydrochloric acid, and partly to the imperfect precipitation, by aulphmetted hydrogen, of solutions containing arsenic.Again, the only safe method for the separation of arsenic from antimony, is the one proposed by R. Bunsen,t in which the antimony is removed aspentasulphide in the presence of concentrated hydrochloric acid. According to the directions given by him, the arsenic, after the excess of sulphuretted hydrogen has been expelled by a current of: air and the solution heated with chlorine water, is precipitated as As2S,. This does not give as good results for the arsenic as might be wished, and the author, therefore, proposes to determine it in the strongly acid solution, which remains after the pi*ecipitaa tion of the antimony, by a volumetric method, which was suggested by Mob*, but has never been worked out by him. Xt consists, essentially, in ’ reducing the arsenic acid, either before or after removing the hydrochloric acid, and then titrating with standard “Zeitsuhrift fiu.Anal. Chemie., 23,378. ?Liebig’s Annalen A., Chemie. 192, 805.THE ANAILYST. 203 iodine solution. The author assumes that the reduction is complete when.sulphu- rous acid is used (this has been proved by WGhler Ann. A. Chem. u. Pharm. 30,224): A large quantity of the sulphurous acid is used, the, excess of which is removed by a current of air, or by evaporating to Q ; a platinum-spiral being placed in, the solu- tion to facilitate the escape of the gas. According to the author's observations, if the hydro- chloric acid be neutralized before the reduction, the .results obtained are rather high, due to the large quantity of alkaline chlorides which are thus produced.The best results are got by evaporating off the acid, and then reducing. This course is further warranted by the following facts : ftrstly, that arsenic chloride is not reduced, in fihe presence of chlorine, by boiling hydrochloric acid ; and, secondly, that hydrochloric acid of Sp. Gt. 1.10, containing arsenic, distils, after the addition of potassium chlorate, free from arsenic. To test the method, the following experiment, among others, was made : 50 C.C. containing 0.1814 As,O8 were taken and evaporated, .with 200 C.C. chlorine- water and 1 g m . ICCI03, to dryness. The residue was dissolved in 200 G.C. of sulphurous acid, and as much distilled water ; the solution was heated. for half an hour to near boiling, and then evaporated to *, another 200 C.C. of SO, solution were added, and the whole was finally boiled, with the platinum-spiral to Q.I On titrating, 38*9 C;C. iodine solution were required, this was equivalent to 0.1323 grm Ae203, whereas -the theoretical amount was 0.1330 ; a result which leaves little to be desired. Further researches of the author show that it is not necessary that the solution should be boiled, or even kept long near boiling, to insure a complete reduction with sulphurous acid. THE DETERXINATION OF MOI;YBDENUM.-BP OTTO FREIHERR VON DER - PFORDTEN.* The author has been investigating the different gravimetric methods for the deter- mination of molybdenum, and has improved upon the volumetric method, which consists in titrating with potassium permanganate. The following is a short rdszcmd of his researches.I. Gravimetric Methods. Phe author made use of the ordinary ammonium. molybdate, 3(NH4),0, ?MOO, (a) By reduction of molybdic acid to the metallic state. U. Rounnelsberg recommended heating molybdic acid in a platinum tube, though which a current of hydrogen was being passed, to reduce to the metallic state (Pogg. Annal., 127, 281) ; while Debray proposed to reduce first to a lower oxide in a platinum crucible, and then to complete the operation in the plafinum tube. The author has simplified the method by doing away altogether with the platinum tube; his researches &ow that it is possible to complete the reduction in a current of hydrogen, using simply a platinum crucible. The latter is fitted with a perforated platinum cover (porcelain may be used), through which the hydrogen enters by means of a suitable tube.The heat is supplied by the blowpipe flame. The analysis of ammonium molybdate is conducted in * Zeitsohrift fiir And. Chemie., 23, 413. + 4H,O, in his experiments.204 THE ANALYST. the following may :--The crucible is first kept at a temperature of 1'70" C. for several hours in the air-bath; this prevents spitting during the ignition. It is then gently heated in a slow current of hydrogen, tho heat being allowed to rise slowly. The reduction is completed by a strong ignition xith the blow pipe, about half an hour being required for 0-2 grm. of metallic molybdenum. Care must be taken, after the operation, to well clean the crucible by ignition and successive treatments with nitric acid and ammonia. This method is applicable to neutral solutions containing molybdic acid, if they are first-precipitated by mercurous nitrate according to Rose's method.(6) By reduction of molybdenum trisulphide to disulphide. This is suited for the analysis of acicl solutions containing molybdic acid. It was &st described by T. Paul Liechti and B. Hempe. The acid solution is made alkaline with ammonia, ammonium sulphide is added, and it is then allowed to stand €or 12 hours. The molybdenum forms a molybdic trisulphide, which is soluble in excess of ammonium dphide to a deep brown liquid. The solution thus obtained is decomposed by adding sulphuric acid in excess; and the precipitate of molybdic ti*isulphide and sulphur'is collected upon a weighed filter, mashed with mlphuretted hydrogen water, and dried at 100-105° C.till the weight remains constant. A weighed part of the dried precipitate is then converted by ignition, in an atmosphere of hydrogen, to molybdic di- sulphide ; and from this the molybdenum is calculated. The author obtained good results with this method, but recommends heating with a simple Bunsen burner, as a too powerful ignition with the blow pipe causes a partial reduction to the metallic state. 11, The Polumetrio Nethod. The author reduces the molybdic acid completely in hydrochloric acid aolution, and then titrates with potassium permanganate, without excluding the air. The suboxide, first formed, is subsequently transformed into sesquioxide. The analysis is conducted thus :-To the solution of the salt, containing about 0.3 grm.MOO,, is added 50-60 C.C. of a 27 per cent. solution of hydrochloric acid, together with 8-10 grms. of zinc, in which the amount of iron has been previously determined by titration. As soon as the solution assumes a yellow colour the vessel i s cwkjd, before all the zinc has been used; and its contents are washed into a porcelain dish, containing 40 C.C. of a daute sulphurous acid solution and 20 0.0. of a solution of manganous sulphate. An equal quantity of water (about a litre) is now added, and a considerable amount of standard permanganate solution run in, the liquid being, meanwhile, well stirred. The titration is complete when the solution becomes faintly pink. Allowance must be made for the iron contained in the zinc, and the permangate required to colour the mass of liquid.The results are accurate. The mean of 14 analyses was 81.52 per cent., MOO, (the maximum being 81.78 per cent,, the minimum 81.28 per cent.) while the calculated quantity was 81.55 per cent. THE DETERMINATION OF PHOSPHORIC Acm. Otto Freiherr von der Pfordten, the author, by ingeniously combining the volurne- tric estimation of Molybdenum (as described above), Fith the precipitation of pholrrphoric acid by ammonium molybdate, has produced it useful titration method for the determina- tion of phosphoric acid.The phosphoric acid is fir& precipitated by ammonium molybdate, in the usual manner. (Note.-The ammonium rnolybdate solution must be clear, and filtered from any deposit before use).To cause the precipitate to separate out better, the beaker containing the solution should be warmed in the water bath; the precipitate is thus freed from molybdic acid. The ammonium phospho-slolybdate thus obtained, is washed with the filter pump, by a nearly saturated solution of pure ammonium sulphate, till a drop, on the addition of ammonium sulphide and weak acid, gives no dark colouu.. The precipitate on the filter is then dissolved in a small quantity of ammonia, and diluted to a knom volume, of which a measured portion, containing at the most 0.3 grains, but not more than 30 0.0. is used for the reduction, This takes place as described above. It is advisable to make several titrations, and to take the p a n of- these. From the permanganate required for the oxidation, first the Wqlybdenum is calculated, and from this the amount of phosphoric acid is deduced.A Ferric phosphate contained, according to gravimetric methods, 36.99 per cent, P,O,; the volumetric method gave from 35*85 to 35.97. A Guano-phosphate gave The method is always applicable when the phosphoric acid can be separated by ammonium molybdate. The author recommends it egpecially for cases where the pre- sence of other bodies (Fe, Al, &a) has hitherto prevented the use of a titration method, CraVirnetricaUy - - - 21-19 per cent. P,O, Volwnetdcally - I 21.88 THE DETERMINATION OF PHOSPHORIC ACID IN Sorr;s.-P. DE GASPARIN. P. de Gasparin gives in the Comptes Rendus (96, 314) the following method for the estimation of phosphoric acid in soils :-20 grms.of the finely powdered and sifted earth are treated in a porcelain dish, with sulphuric acid (I : 5 ) as long as any effer- vescence takes place ; 80 c.c:of aqua regia (lHN0, : 3HC1) are then added, and the mixture heated on the water bath, till the liquid becomes syrupy, diluted with cold distilled water, and washed on to the filter with hot water. The filtrate is precipitated with ammonia, collected on the filter and dried. The dry precipitate is heated in a plat- inum crucible to redness, digested with cold dilute nitric acid ( I : 40) and filtered. The filtrate contains, according to the author, all the phosphoric acid. It is concentrated on the water bath, p~ecipitated with molybdic acid, and the phosphoric acid finally deter- mined in the ordinary way as magnesium pyrophosphate.T H ~ DETERMINATION OF THE TECHNICAL WORTH OF CALCIVM TARTRATE.-~EI~ERT.~ The principle of this method depends upon the fact, that calcium. tartrate is decom- posed by boiling potassium carbonate (1 to 2 hours on the water bath) into neutral potassium tartrate and calcium carbonate. The filtered solution is evaporated ; enough concentrated acetic acid is added to the warm liquid, to form wine-stone (bitartrate of , ._ - t Zeitsohrift fiir And. Chem. 23, 358.PO6 THE ANALYST, - ~ - - potash), and the whole allowed to stand for some hours. It is then treated with alcohol (90 per cent.), filtered, mashed with alcohol, and h&y.titrated. The correctness of the results depends upon the following precautions :-(1) The potassium carbonate must be added only in slight excess ; (2) Acetic acid must be added only in a corresponding excess ; (3) The washing must be carried on sufficiently long ; (4) The mixture of potas- sium carbonate nnd neutral calcium tartrate, to which the acetic acid has been added, must still contain water on the addition of alcohol. For titration a potash solution is used, which serves for estimating the acidity of wines.Its strength is snch that 1 c,c, will neutralise 0.01 grm. tartaric acid or *02608 bitartrate (mine-stone). The following correction is given by the author for the bitartrate remaining in. solu- tion for every five grms. of calcium tartrate, 0.33 per cent. bitartrate of potaah i s to be added to the quantity which has been found by titration.F. H. H, Bonn, 21st Oct., 1884. IN the British Hedioal Jownzal for 11th October, are found the following :- RENARKS ON TESTS FOR ALBUMEN IN TEE URINE, NEW AND OLD. BY GEORW JOHNSON, M.D., F.B.S. IN a paper on the above subject in the recently published Xanohestw Midioal Chronicle, Dr. William Roberts, referring to the fact that the urine in health contains various forms of albuminoid matter, expresses his belief that the new tests for albumen which have recently been brought into prominence, especially picric acid, tungstate of soda, potassio- mercuric iodide, and the acidulated brine-test, ‘6 produce frequently in the wines of perfectly healthy persons, a reaction which is undistinguishable from the reaction which indicates digease or abnormality.” This point was put to the proof by the examination of the urine of thirty-one healthy persons-students, candidates for insurance, and others, who exhibited no signs of disordered health, and in whose urine heat and nitric acid gave no indication of albumen.Dr. Roberts, of course, needs not to be reminded that albumen, in greater or less abundance, and for long periods of time, may be unquestionably present in the urine of persons who exhibit no signs of disordered health. If this were not so, albuminuria would not be so frequently unsuspected and overlooked as it is. Dr. Roberts proceeds to state that ( I the acidulated brine-test gave a reaction in eleven cases, picric acid in fourteen, the tungstate test in twenty-eight, and the mercuric iodide in tmenty-nine cases.” Deferring for the present what I have to say of picric acid, I should have expected, from observations which I have quite recently made, that the other three tests would give a slight but appreciable reaction in every specimen of normal urine.It is a fact; that all normal urine contains a small but variable proportion of mucus. (See the-article Mucus,” in Watts’s Dictionary of Ohemisty, vol. iii., p. 1059.60,) It is also precipi- tated, as Dr. Oliver has shown ( I Bedside Urinary Testing,’ p. 37), by citric acid. The addition of a small quantity of acetic or citric acid to normal urine gradually renders it Now, mucin is precipitated by dilute acetic acid and mineral acids.THE ANBEPST. 207 slightly but decidedly turbid, by coagulating the mucin ; and Dr. Roberts mentions the fact that, when nitric acid is added to albuminous urine, the albumen is thrown down just above the line of junction of the two liquids, while the miicin is brought into view towards the upper part of the column of urine, where it gradually forms a-diffused haze quite distinct from the opalescent haze at the line of junction.” To this I may add that, when nitric acid is placed at the bottom of a column of normal urine, a diffused ham of coagulated mucia may commonly, after a time, be seen near the upper part of the column.Seeing then that mucin is precipitated by both mineral and vegetable acids, we are at no loss to understand that any test containing one or other of these agents should give a reaction with normal urine. The acidulated brine contains hydrochloric acid, the tungstate of soda and potassio-mercuric iodide require the addition of either citric or acetic acid before they act as albumen-precipitants ; and they one and all, by the reaction with mucin, slowly cause, in most, if not all, normal urines, a cloudiness more decided than that which results from the action of the acids alone.Withpicric acid, however, the oase is entirely different. In the form of a saturated aqueous solutioD, and uncombined with any other agent, it is a most delicate albumen-precipitant, but it gives no precipi- tate in normal urino unless an acid, such as citric or acetic acid, be added to it. This can readily be proved by the following experiment. Take about a drachm of freshly passed normal urine, and add an equal bulk of picric acid solution.The yellow mixture will remain quite clear, unless, as sometimes though rarely happens, some turbidity results from a deposit of urates, which would be at once removed by heat. Now add a few drops of dilute acetic or citric acid, and the mixture will, in aminute or two, become hazy from precipitated niucin, the haziness occurring much more slowly than the immediato opalescence, which results from the presence of a slight trace of albumen, but, like that, being unchanged by heat. Another experiment consists ill adding acetic or citric acid to normal urine, then, after waiting a minute or two to complete the coagulation of the mucin, passing the urine through a filter and adding picric acid to the filtrate; when the mixture will remain quite free from turbidity.I have tested many hundred specimens of normal urine with picric acid, and I confidently assert that in such specimens, no precipitate or haziness occurs when unmixed picric acid is used as the test-agent ; and it may be that the different results with this test obtained by Dr. Roberts are due to his having added acetio or citric acid to the picric acid in his experiments. The only precipitates other than albuminous which may result from pic& acid, employed alone, are urates which rarely occur, except when the mixture is allowed to stand for some time ; peptones which I have met with only twice in as many years; and vegetable alkaloids, such as quinine, *hen lmge doses are being taken. These all differ from an albuminow precipi- tate in the fact that they are readily and completely redissolveii by heat, while thsy may be distinguished from each otlier by the microscope‘ (See the author’s locttires OIL ‘ Albumen tmJ Sugar Testing,’ p.11, Smith, @der and Go.)-____--- 208 THE ANALYST. - ---________ ~ - - It appears, therefore, from very numerous and careful observations, that albumen is the only substance found in the urine which gives with picric acid aprecipitate insoluble by heat. The difference, then, between pic1.c acid and the other new tests for albumen is this-that picric acid, unmixed with other reagents, while it is a most sensitive and trustworthy test for albumen, gives no reaction with mucin. On the other hand, the potassio-mercuric iodide, tungstate of soda, and brine do not precipitate albumen unless when combined with an acid ; and this combination gives a reaction with mucin, which is not distinguishable €rom a minute trace of albumen.I have been in the habit of using the potassio-mercuric iodide only as a check upon the picric acid test, when small quantities of albumen only were present, and, until lately, had not thought of applying it to normal urine. I now find, however, that the test-liquid, when acidulated-as it must be, to act at all-gives a distinct opalescence in most, if not all, normal urines. I find, too, that after the ~nucin has been removed from normal urine by its coagulation with acetic or citric acid, and subsequent filtration, the addition of the potassio-mercuric iodide to the filtrate causes a decided opalescence, which is probably due to the precipitation of some substance other than mucin in the urine.In testing urines which contain a mere trace of albumen, it is important to remove any turbidity that would interfere with the process. Urates would be removed by heat, suspended mucus and other particles by filtration. The addition of the picric acid solu- tion to a twbid specimen might give a fallacious appearance of coagulated albumen, when, in fact, there is nothing more than Bome hicreased opacity, due to the yeUow staining of the suspended particles. Picric acid is itself sufficiently acid, when added iu excess, to dissolve and clear a, phosphatic tuybidity. In the rare case of the urine being so highly alkaline as to prevent the coagulation of the albumen by an excess of picric acid, the plan is to add sufficient citric or acetic acid to neutmlize the alkali, then to filter, and add the picric acid to the fi1ti4at e.It appeai's, then, that picpic acid as a test fop albumen is more free from fallacy than any other, not even excepting heat and nitric acid, which Dr. Roberts expresses his deter- mination to fall back upon. Of course, in a doubtful case, no one would neglect to apply more than one test. That pic& acid is a more sensitive test than heat and nitric acid js eaaily proved by taking a highly albuminous specimen aYrd gradually diluting it up to the point where-though theae testa fail to detect it-picric acid still gives a diatinot reaction. The Main advantages of picfic acid as ft teat for albumen are the following :-It hstantly detects a saall amount of albumen which nitric acid would indicate only slowly or not at all; while, on the one hand, anjnsufficient addition of the test does not, as is the case with nitric acid, prevelit the subsequent coagulation by heat ; neither, on the other hand, does an excess of picric acid redissolve the precipitate, as does an excess uf nitpic acid. Por bedside urinary testing, the portability of the innocuous powder is a great convenience. $he fact that, with caustic potash, it is an infallible qualitative and quantitative twt for augai; may be said to be more than double its value as an uainaryTHE ANALYST. 209 - -------- test. For bedside use, Mi. Hawksloy, 35’7, Oxford Street, makes a waistcoat-pocket test-case, consisting of a test-tube four inches long, in which are packed two smaller tubes, one containing picric acid powder, the other grain-lumps of caustic potash, and also a s m d spirit lamp, These are enclosed in a metal case, not; much larger than a pencil-case. Another small case contains a nipple-pipette, which, amongst other uses, is convenient for conveying urine from .the vessel to the test-tube. The picric acid which is used for sugar-testing should be purified by recrystallisa- tion. The commercial samples usually give a red colour when boiled with liquor potassm; and 1 lately saw an impure sample, which not only gave this red colour, but the liquid was rendered turbid by fine granules. The impurity was removed by solution and recryst allization .

ISSN:0003-2654    

DOI:10.1039/AN8840900202

出版商:RSC    

年代:1884

数据来源: RSC

摘要:

R E V I E W 8 . T m JOURNAL OP MICROSCOPY AND NATURAL SCIIIENCE, BEING TEE JOURNAL OF THE TIXIS journal, which will in future, me understand, be published quarterly by Messrs. BailliGre, Tindall and Cox, is an exceedingly interesting one. The Society was, we are informed, founded in 1873 to aid in the study, discussion, and circulation of microscopic objects, and to advance the pursuit of natural science among its members. It is divided into thirteen circuits of about twelve members each, arranged geographically. A box of slides, accompanied by MS. book for the insertion of notes and memoranda, is sent by the hon. secretary, at fortnightly intervals, to the first member on one of the circuits ; who, after keeping it for three days, must send it on by post to the next on the list, and he to the following one.When it has gone round the circuit, the last member returns it to the hon. secretary, who will then forward it to the &st member of the next circuit, and so on, until the slides have been seen by the whole of the Society. Each member ia expected to contribute six slides annually, which are returned to him after they have been round the circuits. Ladies, as well as gentlemen, may be elected members of the Society. As a rule, the journal, being conducted by the members, as it were, cow antore, is very readable, andnot only so, but exceedingly instructive and interesting to microscopists. ON THE HE-ILTIIY MANUFAOTURE OF BREAD. By Beqy'ami~ Vwd Richard8on, lcI.D.t F.R.8. London, Baillidre, Tindall and Cox. THIS is a well-written pampldet, designed to advance the taste of the public for apated bread manufactured upon Dr.Dauglish's system. There ia nothing particularly novel or atpiking in its composition, but the name of its authoi. will, doubtless, lend weight to it, and help to convince the public in favow of his views. Itt of coume, deals in a popular and easily comprehensible manner with the chemistry of fermentation. b m r A L CAkms. By Hew?/ sews%, XI?. C"8. ard s.D.8. Reprinted from the Jouraal ALTHOUGH not a strictly chemical work, this book is yet interesting to the chemist and microscopist, as the ituthor takes the view that carie8 of the teeth has a distbctly POSTAL MICROSCOPICAL SOCIETY. Edited by Alfred Men, 35012. Secretary. of the Byitish Dental Association, London, Bailbe, Tindall and Cox.-- ------- THE ANUYST.-_-_I_----- 210 --- chemical origin, being started frequently by a generally acid state of the saliva. These a d s , according to Mr. Bewill’s viers, are principally malic, butyric, and acetic, and are the products of chemical change and fermentation, set up in the fragments of organic matter-food, mucus, and epithelial scales-which are commonly present in the mouth, and lodged upon the teeth. Acid may be derived from several other sources. It may be secreted by the fl~zucous membrane. The normal secretion of the membrane is small in quantity, and slightly acid. I n health, the acid is at once neutralised by the alkaline stliva, with which it mingles; but when the membrane is congested or inflamed, t.he mucus increases in quantiw, and becomes more sfxongly acid in character.Then again, many forms of organisms themselves produce acid. Acid is eructated in many gastric disorders ; and an acid, instead of alkaline, reaction is shown by saliva in several as- eases. The whole work, dealing as it does with tho nzicroscopical and chemical characters of sound and decayed teeth, is evidently the product of much thought and research, and the arguments contained in it, are, in many places, exceedingly striking. The treatment recommended is not within our province to discuss, but generally qeaking it is alkaline (use being made of borax) and antiseptic. The author does not agree with the wholesale condemnation of the use of the tooth-pick we freqiiently see indulged in, but on tho contrary recommends its employment every night before going to bed, followed by a good rinsing of the mouth with the alkaline and antiseptic lotion, for keeping t.he teeth in good condition. It is a book that dl really enhance the author’s fame, both d t h his fellom professional men, and with the public who happen to come across it.

ISSN:0003-2654    

DOI:10.1039/AN8840900209

出版商:RSC    

年代:1884

数据来源: RSC

摘要:

210 THE ANUYST. LAW REPORTS. tnasket gardener and milk vendor, of Leighton Buzzard, again appeared to adjourned surnmonq charged with having sold to Supt. Shepherd, on the 318t of July, milk which was alleged to have been adulterated with 12 per cent. of water and deficient in butter-fat to the extent of 20 per cent. This was the t k d time this case had been before the court. On the h t occasion the defendant challenged the certificate of Dr. Stevenson, of Guy’s Hospital, London, the county analyst ; on the second he produced a certifi- cate from 36esm. Wigner and Hmland, of London, who, after. analysis, stated that a portion of the mmple of milk taken from defendant contained s/10 per cent. more of butter-fat than the limit laid down by the Society of Analysts, though they added that it was cliflicult to say whether or not the milk had been watered, owing to its decomposition when analysed.Under these oircumstances the mse fvas referrod to Somerset House, .and 8 portion of the sample forwarded thither for final analysis. A cefifi- cattsfrom Somerset House was now produced by Supt. Shepherd, and read by the Chairman, as follows :- ‘‘ Laboratory, bcSomerset House, W.C. ‘ 6 The sample of milk referred to in the annexed memorandum, and marked Bedfordshire, 11-9, wag received here on the 17th inst. The bottle was securely sealed. We hereby certify that we have analyaed the milk, and declare the results of our analysis to be as f0llow.g :-Non-fatty solids, 7.65 per cent.; fat, 2.59 ; water, 89.76; ash, ‘i3. From a consideration of these results, and after making for natural loss arising from the decomposition of the matter through a period of fi% dayfi, we are unable to a m that water has been added to or cream abstracted from the milk.DISPUTZD MILK CASE, “ ALLOWANCE FOn DECOXPOSIFION ” NOT HOLDING Goon-Thomas E&etou, 46As witnas our hands this 27th day of September, 1884. (‘ R, BANHSTEH. (‘ G. LRWIN.” Dr. Stevenson, now called to pemonally support his certificate, said he was public analyst for the county of Bedford. On July 31st last he received three samples of milk from Supt. Shepherd, numbered ll-& 11-9, 11-10. The bottle’mark 11-9 was now produced. After analysing the milk therein he gave the ce~fimte before tho court, whioh ma6 correct aooount of the &ual~ds and hb opinion therbon. HdTHE ANALYST.211 made two analyses, and they agreed very closely. He was assisted in the analysis, but supervised the whole process. On Soptember 18th the defendant came to his laboratory, and was shown the bottle marked 11-9, as it remained after the analysis. He said he had been summoned, and suggested that a mistake had boen mado, Witness said he would analyso the milk again. He made two new analyses from the milk left, and fromthe result he found that he could have made no mistake, and that hi8 cer- tificate was a correct one. T h mean percentage of fat should be from 32 to 3+ per oent., but this sample wae deficient to tho oxtent of 20 per cent. On the 22nd of September defendant brought witness another sample of milk. He said it was from the same cows as the original milk had been taken, and that the cows were being fed in the same manner as in July, and that the sample was a fair one of the wholo yield of tho cows.Witness analysed that milk, and found it of very nearly the average quality. By adding 9# per cent, of water to the last sample, and taking away 23i per cent. of fat, the two aamples would be brought together in quality. His conclusion was that the deficiency of fat in the original sample was not natural. Cross-examined by Mr. Grayson, witness said he was appointed analyst for Che ooiinty of Bedford in 1872. He made 400 or 600 milk analyses in the course of a year. He was present and took part in the analysis. He employed assistants. He had paid a deal of attention to milk analysk He was quite certain that his figures was correct, and had kept a record of them.Milk varied occasionally in quality according to the cows. It contained 87 to 88 per cent. of water naturally, and when it became decomposed it did not give such a good result. In a decomposed state the percentage would not inorease more than about 4 per cent. It might get up to 90 per cent. if very much decomgosod, Milk containing 10*GO 01 solids would not be consistent with genuine milk, with no water added, if a cow was milked under abnomd circumstances. Mr. Grayson here quoted from Dr. Tidy, who had, boforo a Select Committee of the House of Commons, drawn the line at, 10 per cent. of total solids, and wouId not say that a sample of milk containing that quantity was adulterated : but Dr.Stevenson would not say that he agreed with Dr. Tidy-he would not rest his opinion upon such figures. He did not know that the standard was once higher, and that the analysts, finding out that they were doing an injustice to honest men, had to give up the standard of their own creation. Mr. Haslam inquired if 10 per cent. was the Government standard. Mr. Grayson said there was nostandard, but the defendant’s milk was per cent, in fat higher than the standard allowed by the Society of Public Analysts. Dr. Stevenson said he belonged to the society, and must correct, a misapprehension. It was not yl0 per cent. above the standard, but above the limit allowed by the society. l?urther eross- examined, Dr. Stevenson added that defendant’s was poor milk, and he thought no analyst would have difficulty in discovering that fact.His analysis had been made under more favourable circumstances than that of Messrs. Wigner and Harland. Had theirs been made earlier, it would have been more favourablo to the defendant in some pai*ticulars. The Somerset House analysis convinced him that he had analyscd the same milk. Witness had in his experience made mistakes-two, he believed. No analyst would be human if he was not sometimes in error, but in the two cases t o which he referred he had made further inquiry, and, having satisfied himself, admitted the mistakes, which, however, were not in analysis, but in numbering. Good milk ought to contain twelve per cent. of solids, and he should be very suspicious of any below 11+ per cent.Mi. Grayson in defence, said he did not think there would be any difficulty in the Bench coming to the conclusion that this was genuine milk. There had been no complaint against it on the part of the public, and he thought it a very serious thing that the machinery of the Act should be put in motion again& the defendant. In the absence of complaint there had been no reason t o analyse this milk at all. The Superintendent of police, in the course he had taken, ought to be supposed to have some reason for suspicion. The chairman said that was not so. The Superintendent periodically submitted for analysis almost everybody’s goods. Xr. Grayson said that two years ago defendant’s milk had been tried and found genuine. Since that time he had been specially careful ; he had not watered his milk, and no complaint had been made res- pecting it.On the last occasion that this case was before the court Messrs. Wigner and HarIand’s certificate left a doubt ; and now the Somerset House certificate did not say the milk had been watered; and this ldAar certificate, he ctontended, entitled the Benoh to give the defendant the benefit of the doubt. He rested his defence upon these two latter certificates. Had there been adulteration, it could have been easily ascertained. He believed he was defending an honest man, who had sold an honest article. They had now two cerlifioates one way, t o one the other, and he considered it a cruel hardship to summon this man without came, beside which he did not think that Dr. Stevenson had given his evidence in a straightforward manner.The Chairman, who had during the cross-examination of Dr. Stevenson requested Mr. Grayson to alIow the doctor to finish his sentences before putting furher questions, hero said the Bench did not agree with the remark that evidence had not been given straightforwardly. Nr. Grayson said he would give way, but he was puzzled t o know212 THE ANALYST. how the defioiency of fat and excess of water had been ascertajned. The Nagistrates now retired to oonsult together, and on returning into Court the Chairman said the Bench had given careful attention to this oase, and they felt that it was not without its difficulties. In coming to a decision they had taken the most favourable view of the defendant’s circumstances. At the mme time, they had carefully prepared a table of the three analyses, and did not find the great discrepancies which the gentleman engaged for the defence endeavoured to draw attention to.Dr. Stevenson reported 10.60 per cent. of solids ; Messrs. Wigner and Harland, 10.34 per cent. ; and Somerset House, 10.24 per cent. It would be observed that the solids of Messrs. Wigner and Harland and of Somemet House were slightly less than those of their own analyst, but that might be amounted for by the deterioration in the milk. Again, in the two other things that went to make up the total, the analysts’ reports were pretty well agreed. Dr. Stevenson said there were 2‘46 of fatty and 8’14 of non-fatty matter ; Messrs. Wiper and Harland put the fatty matter at 2-71 and the non-fatty at 7-63 ; and Somerset House gave the fatty at 2.59 and the non-fatty at 7.65.Dr. Stevenson said 89.40, Messrs. Wiper and Harland 89-66, and Somerset House SS*7S. All the principal figures agreed, as did also the decimals to a very considerable extent, Somerset House giving rather more water and less solids than the other reports. With regard to Messrs. Wiper and Harland’s concluding remarks, the Bench did not see much more than a negative opinion; and the analysts of Somerset House said that after the length of time that had elapsed, they were unable to affirm that water had been added or cream abstracted. They did not affirm that they had not. Under all these ciroumstances, and considering that the superintendent had only done his duty in the matter, and had not attempted to be h a d or harsh, and taking into consideration the serious importance of the case to the defendant, they had decided to deal with the case lightly.A fine must be inflicted, but as small as possible. The ex- penses amounted to very nearly $1, and the defendant would have to pay $1, including costs. ANOTHER CASE INvoLVmct ‘‘ ALLOWANCE FOB DEcom?osITsox.”--Joseph Pickering, a milk dealer, of 68, Lockton Street, Bow, appeared to answer an adjourned summons taken out against him at the instance of William Talbot Harrison, one of the Sanitary Inspeotors to the Poplar Board of Works, for selling as pure, milk which had been adulterated to the extent of thirteen per cent. with water. Mr. Famifield appeared to prosecute. The case, which possessed some very remarkable features, has already been twice before the Court.On tlie first occasion the certificate of Mr, Young, the analyst to the B o d , was put in, and that stated that the milk was adulterated with water to the extent named. The defendant, however, denied that there was any adulteration, and produced a certificate which he said he had received from Professor Redwood, setting forth that the milk was pure. The case was then adjournedfor the attendance of the professor; but when it came up on the following week, the defendant said that he had not been able tosecure the professor, as he was out of town, but that he (the defendant) should like the third sample of milk, which is generally retained in case suoh a demand is made, to be submitted to the Government analyst at Somerset House.This was accordingly done, the summons meanwhile being adjourned sane dbe. When the case now came on, Mr. Lushington said that since the last adjournment he had received a certificate from Somerset House, aigned “Riohard Bannister” and (‘ G. LeWin,” whioh stated that they had submitted the sample of milk sent them to analysis, and from a consideration of the results thereof-not losing sight of the time the milk had been kept before it was forwarded for analysis-they {the signatories) could not affirm that any water had been added. Under these circumstances, he (Nr. Lushington)‘shodd dismiss the summons. Each party would have to pay 5s. 3d. towards the expense of the Somerset House analysis. The defendant asked for his own expenses, but his worship declined to grant them. BOOKS, &c., RECEIVED. Then as to water. The Chemist and Druggist ; The Brewers’ Guardian ; The British Nedioal Journal : The Pharma- ceutical Journal ; The Sanitary Record ; The Miller ; The Provisioner ; The Practitioner ; New Remedies ; Proceedings of the American Chemical Society ; The Inventors’ Record ; New Sork Publio Health ; The Scientific American ; Society of Arts Journal ; Sanitary Engineer of New Pork ; Cowkeeper and Dairyman’s Journal ; Sugar Cane ; Country Brewers’ Gazette ; The Hedical Record ; The Grocers’ Gazette ; London Water Supply, by Crookes, Odling and Tidy ; Chemical Review ; Independent Oil and Drug Journal and Paint Review ; Science Monthly ; Journal of the Society of Chemical Industry. NOTICE TO O m READERS AND cONTRIBUTORS.-I?3 future law reports will not be insertedin the ANALYST, unless some really novel point of procedure, or roference under the Act is involved. Our confreres are earnestly requested t o send us cuttings from local journals whenever siich cases occur, but not otherwise.

ISSN:0003-2654    

DOI:10.1039/AN8840900210

出版商:RSC    

年代:1884

数据来源: RSC