摘要:

PROCEEDINGS OF THE SOCIETY OF PUBLIC ANALYSTS. THE VISIT OF THE SOCIETY OF PUBLIC ANALYSTS TO THE FARMS OF THE AYLESBURY DAIRY COMPANY ON THE ~ T H JUNE, 1887. IN the Julyissue of the ANALYST it wa8 briefly mentioned that a number of members of the Society, in virtue of an invitation from the Directors of the Aylesbury Dairy Company, spent the day, subsequent to the June meeting, at the said Company’s farms, near Horsham, Sussex, and I have thought that we still owe to our absent members a fuller account of this very interesting visit. To commence with a few general notes, the rise and progress of the Aplesbury Dairy Company may not be without interest. When in the year 1865 the cattle plague invaded this country, and also visited the cow-sheds of London, necessitating the slaughter of a great number of milch cows, Mr.G. Mander Allender, who for some time had paid great attentian to practical dairy- farming, formed the idea of supplying London with really good milk, direct from the country. I n order to carry this scheme into effect, he, in 1865, founded this Company, of which, since that time, he always has been, and still is, the most active and energetic managing-director. The business was increasing so rapidly that it was soon found to outgrow its Grst abode, and in 1870 it was removed to the specially-built and extensive premises at St. Petersburgh Place, Bayswater. From the very commencement of the business, the supply of pure milk of high quality was made the leading principle. To completely secure the purity of the milk, it was necessary to have a certain control over it from the time it leaves the cow-nay, even more, over the conditions under which the cows are kept, and by which they are surrounded.The Aylesbury Dairy Company, therefore, only enters into a contract for the supply of milk, after the farm in question has been inspected and satisfactorily reported upon by the Company’s sanitary engineer, 88 well as by the iocal medical184 THE ANALYST, -~ ~ officer of health, with regard to sanitary conditions of cow-sheds, milk rooms, etc., special attention being paid to drainage and purity from contamination of the water used for cleansing purposes. Further regulations in the contract, which the farmer desirous to supply the Company with milk is obliged to sign, provides for the utmost cleanliness in handling the milk, the notification of the occurrence of contagious diseases in the district, on the farm, or in the house of any person employed on the farm.If, in consequence of any disease existing on the farm, it should be deemed advisable to stop the supply of milk, the sender is guaranteed to sustain no loss what- soever. On the other hand, the farmer is liable to heavy fines in the case of neglecting the provisions of the contract. It is scarcely necessary to say that at the Bayswater premises the most perfect arrangements exist for most thoroughly cleansing, by means of boiling water, steam, etc., of everything coming in contact with milk, The whole of the employes and the premises are under the supervision of a medical officer, to whose knowledge every case of sickness, no matter however slight, ib brought.Every man in the employ of the Company is also bound to inform the secretary of any case of infectious disease occur- ring in his family or the house he lives in, Every churn of milk entering the dairy has always been tested by thermometer and lactometer for temperature and specific gravity, and, previously to 1880, a number of samples were sent regularly once a week to an eminent analyst. But this system did not seem a sufficient protection, and in the year mentioned a fully-equipped analytical laboratory was established, and put under the charge of Dr. Vieth. Here a more extended and thorough control over the milk passing through the business is executed than exists anywhere in the world.Attendants at the Society’s meetings and readers of the ANALYST are well acquainted with the nature and extent of the work accomplished in this laboratory through Dr. Vieth’s annual reports. It is obvious that for various reasons it must be considered a drawback to such a large concern to be entirely dependent on purchased milk. The desirability of being not distributors only, but also producers of milk, made itself felt more and more by the Aylesbury Dairy Company, and in 1884 led t o the purchase of the Itching- field Estate, comprising an area of 1,400 acres, and divided into six holdings, which, after they had successively come in hand, were all thrown into one well-arranged farm. The farm is situated in the county of Sussex, within 1H miles to the south of the town of Horsham, and is intersected by the Mid-Sussex line of the London, Brighton, and South Coast Railway.The general character of the knd is that of a readily workable loam, resting on a calcareous sandstone, which secures a good natural drainage. The estate has the advantage of a constant supply of pure water. This is obtained from a lake, fed from springs which have never been known to fail in any season. From this lake the water is pumped up to a tower, and also into a large reservoir, holding half-a-million gallons ; thence the buildings and fields are supplied by gravitation. I n no instance are animals allowed to drink from ponds. The buildings are, with very few exceptions, new constructions of a suitable and commodious, though by no means extravagant, character.To this estate, then, the visit of the 9th of June was paid. The visitors were met byTHE ANALYST. 185 001. Talbot and Mr. Burls, Directors of the Aylesbury Dairy Company, at Victoria Station, where a special train was in waiting, taking the company to Horsham, and thence to the private siding on the estate. The numerous company included the President, Vice-Presidents, Secretaries, and a good many members of the Society of Public Analysts, as well as many Medical Officers of Health, and a number of other gentlemen, among them Mr. Lennox Peel, C.B. ; Mr. Stephen Terry, C.E., Local Government Board ; Professor Brown, C.B. ; Mr. Cope, Agricultural Department, Privy Council ; Professor Robertson, Principal, Royal Veterinary College ; and others.On quitting the train the visitors were received by Mr. Allender, the Managing Director and founder of the Company, and on their way to the chief farm (Stammerham) had an opportunity of inspecting a number of animals representing the various breeds kept on the estate, which were paraded, their respective characteristics being pointed out. There were pure shorthorns, and what are known as (‘ dairy ” shorthorns, animals not entitled to be entered in the herd book, and yet many of them highly bred. Shorthorns are perhaps the most useful all-round animals for the dairy farmer, producing as they do, if properly selected and fed, milk good both in quantity and in quality, and are yet useful as beef-makers. Then came polled Norfolks, hornless, as their name implies -grand red animals.Mr. Allender thinks highly of this breed, and is inclined to increase the number of them on the Company’s farms. Next, the pretty Jerseys, which, if not yielding as much milk as the larger shorthorns, far surpass all other breeds for quality, seven per cent. of fat being by no means uncommon in the milk of these little animals. A still smaller cow, the Kerry and Dexter Kerry, are almost a speciality on the Company’s farms, their herd of these useful little beasts already numbering sixty or seventy. They give an astounding quantity of milk for their size, and it is of excellent quality. Sussex cattle are also kept, as they are the cattle of the district, and although ementially a beef-producing breed, give milk of good quality, although in small quantity.Each breed is kept pure, part of the Company’s business being the sale of cattle, as well as the production of milk. The herd at present numbers nearly 400 head, and it was stated that it will be shortly increased to 500. The Tamworth, a pig of a sandy red colour, is principally kept ; and indeed this breed is a speciality of the Company, its chief point being a large percentage of lean meat, as distinguished from the terribly fat animals-masses of lard-one usually gees. Very great numbers of these pigs are exported by the Company, chiefly to the north of Europe-Germany, Denmark, and Norway. Soubhdown sheep, and any quantity of poultry of various pure breeds, complete, with exception of the horses, the live stock of this large farm. This is plain, substantial, and very spacious, light and air being secured to the highest degree.The drainage is perfect, simply because there is not a drain in the whole range, every- thing in the way of liquid finding its exit direct into the open air. The floors are impervious, being specially constructed of a mixture of the best Portland cement and sharp sea grit-a mixture which not only becomes as hard as granite in the course of a short time, but is capable of being made perfectly smooth and thoroughly water-tight. Pigs, of course, are maintained as consumers of the by-products of a dairy. After inspecting the cattle a move was made to the Dairy.186 THE ANALYST. Here the milk is brought direct from the cow-houses, I f required to be sent to London as milk, it is poured into a large vessel holding some 500 gallons, and from thence it passes over the refrigerators by which it is deprived of all animal heat, and thence flows into the cans in which it travels to London.If cream be required, the milk is passed through a centrifugal separator which enables the cream, in a perfectly fresh condition, to be despatched to London within two hours of the time the cowsaremilked. The skim milk is at once sent off to that portion of the Company’s estate where the celebrated herd of Tamworth pigs is kept, and thus the young pigs are rapidly grown into valuable animals. On leaving the dairy the visitors found themselves in the first of the pair of cow-houses, in each of which eighty cows are kept. The houses, designed and built by Mr. Allender (as indeed are all the buildings) are especially worthy of notice.Space, light, and ventilation have been most carefully studied. The dimensions are 172 feet long, 40 feet wide, and 24 feet high to the lantern, which extends the whole length of the houses, thus affording to each of the eighty cows over 1,200 cubic feet of space, or 50 per cent. over and above that fixed by the Metropolitan Board of Works. In addition to ten large windows on each side of the houses the lantern is lighted through- out its entire length. The mangers are of hard Staffordshire ware, and in order to guard against any possible chance of stale food ever being left, between each meal a constant stream of water is allowed to flow through the mangers. With exception of the men and boys actually employed in attendance upon the cows, no other persons are permitted to enter the houses, except in company of some chief official, and none of the ordinary farm hands are ever allowed in.The milkers are inspected every week by the medical officer of the Company, and a certificate is signed by this gentleman a8 to their sanitary condition. There are a great number of other extensive buildings upon the Company’s farms (as shown on the accompanying map), notably a covered yard, supposed to be the largest in England, capable of housing one hundred head of cattle; a fine range of bull boxes, containing nine bulls of different pure breeds ; stables, etc., etc. The Stammerham buildings alone cover an area of nearly ten acres, and form perhaps the largest homestead in the country.After the inspection of the buildings the Company were entertained at luncheon, Mr. Allender occupying the chair. Alluding to the paper read by Dr. Klein on the 27th ult. before the Royal Institution, Mr. Allender said that if the cow were the terrible creature represented by Dr. Klein, all who were interested in dairy work, and in cow- keeping especially, must take measures for observing the signs of disease in the animal, and for preventing the dissemination of the evils alluded to by Dr. Klein. The Company were now breeders of their own stock, and with the exception of male animals they had purchased all the cattle they would ever buy. Every sanitary care was taken of their stock, and the great object of the Company was to provide for the public a thoroughly reliable milk supply.He hoped that that would not be the last visit to Horsham of the public analysts and medical officers of health. The President of the Society of Public Analysts (Mr. ALLEN) said he desired on behalf of his Society (and he hoped he would be supported by their colleagues, the Lavatories and eating-rooms are provided....... I . . .*. o o o ..LLrn..188 THE ANALYST. medical officers of health) to return thanks to Mr. Allender and those associated with him in the Aylesbury Dairy Company, for their very courteousreception that day, and for the very thorough inspection they had been permitted to make of everything on the premises. Speaking as he did for the Public Analysts, he thanked the Company for the opportunity which had been afforded them of thoroughly studying the practical production of milk on the largest and most favourable scale.Many years ago he saw in Punch some specimen questions on useful knowledge, and among them was the question : “ To what are we indebted for milk ? ” Answer : ‘‘ The pump and the chalk pit.” He had not seen a genuine old-fashioned pump on the premises, and although he had looked well for the chalk pit he had failed to discover it. The Chairman had alluded to the Public Analysts’ standard for milk as being 11.5 per cent. of total solids. That body had never suggested anything like that figure. They had suggested 11.5 as the lowest limit, not the standard; and it w&s a great misfortune that people sometimes mixed up the two things.As was known to those present, the Aylesbury Dairy Company’s product averaged 13 per cent. of solids, and he believed that amount to be representative of really wholesome milk, such as could be obtained from properly fed and healthy cows. It was the misfortune and not the fault of Public Analysts that, because there were here and, there cases of worn out or badly fed cows that yielded only 11.5 per cent. of solids, they were, therefore, legally compelled to pass over many cases where initially rich milk had really been watered to some extent. When he got out of the train he thought he was in Arcadia, and on going through the premises he saw that he was in Hygeia, and he was bound to confess that these two words were not always synonymous as they were in the present case.He would like to be allowed to add a word respecting the Company’s chemist, Dr. Vieth. That gentleman was an honoured member and a Vice-president of the Society, and they owed to him some of the most admirable researches on milk extant. He had under his hand the most complete material for the purpose, and both the Analysts and the public were indebted to him for an enormous amount of information he had contributed to the Society’s proceedings on the subject. Dr. WYNTER BLYTH, Medical Officer of Health, 8t. Marylebone, expressed his satis- faction at the way in which large companies took notice of the researches which were made as to scarlet fever in connection with milk. He had always insisted that if we were to drink milk at all the supply must be managed by large companies.The pre- cautions which were necessary could not be observed in oil shops, grocers shops, and such places, where milk was now so much sold. In his own family the milk used was always boiled, and he believed that the milk of the future would be sterilised milk- that was milk heated to 200 degrees for a few hours. Dr. CHARLES KELLY, Medical Officer of Health (West Sussex), spoke of the dangers attending milk by being brought into contamination with impure water. PROFESSOR G. T. BROWN said there was no question at all that milk was a ready carrier of many forms of contamination. The next point was as to the existence of a disease in the cow which should be in the human being transmuted into scarlatina. When Mr. Power’s report was first brought under his notice, the Lord President of the day, Earl Spencer, put on the paper a minute directing him (the speaker) to makeTHE ANALYST.189 an investigation, and since then the investigation had been more or less continuous. At that time, however, the proposal was that a disease in the cow which waa not scarlatina - at least, that was what he had understood from the report - would become changed into scarlatina in man. I n Dr. Klein’s lecture, as he (the speaker) understood it, the proposal was that the cow was subject to scarlatina from the human being, and being so subject, might transmit the disease to man. (“NO, no.”) Well that was what he had gathered from Dr. Klein’s observations, and he might for a moment express his extreme regret that Dr. Klein-he meant the Times reporter (laughter)-had not expressed Dr.Klein’s view sufficiently clearly to enable him to decide, from a simple reading, what Dr. Klein intended to convey on the matter, which was simply tremendous in importance to the agricultural interest. When the editor of the Lancet committed himself to the statement that the experiments which Dr. Klein had made and Mr. Power’s report placed the question beyond the region of controversy, he had committed himself to a swement which no bacteriologist of any importance in the civilised world would endorse. The idea of anything connected with bacteria being out of the region of controversy was worthy of the pages of Pamh. Another journal had put the matter into the region of controversy by a single sentence.The Britisl‘l Medic& Journd said, wait until we publish the report of Dr. Jamieson. When the question was brought into something like practicable shape, it would then undoubtedly appear that investigations of very prolonged and very intricate character would be necessary. They would have to find cases of this disease, which he believed to be about the most common one that occurred in the cow. He, however, fully agreed with Dr. Klein in his remarks on the importance of rendering the infective matter of various diseases which milk would carry harmless bya procsss of heating. As to a remark by Dr. Wynter Blyth, the Aylesbury Dairy Company might sterilise their milk and guard it from infection in every possible way, but that would not protect it from contamination by the retail dealers.[Ur. ALLENDER : Our Company are themselves the retailers, and we have complete control over our milk.] There was no more deadly fluid, taken on the average, than milk, except water ; and as both of them took a very much higher range than any alcoholic fluid, it became a serious question whether dealers in milk, and, if there were such persons, dealers in water, should be properly licensed. It had been very gratifying to look on what they had seen that day, every conceivable method being in operation for the purpose of preventing the contamination of the milk. Dr. HENRY ARMSTRONG, Medical Officer of Health, Newcastle-on-Tyne, said he had been amply rewarded by what he had seen for the long journey he had made to be present that day. One of the facts he would be able to take home with him was that the Aylesbury Dairy Company recognised that 1,200 cubic feet .of space was desirable for housing a cow. Mr. EILNEST HART said he thought that sterilisation would be a very admirable remedy for a great many of the evils of this country. Sterilisation would have prevented the ne- cessity for a great many recent Acts of Parliament. It would have prevented a pat deal of crime ; and applied to speech, it would have prevented a great amount of waste of time in Parliament and other assemblies, He could not think that sterilisation was a principle of any extensive lacteal application, or necessary to any organisation based on s ~ ~ n d principles. He had been struggling t o obtain in his town 800 cubic feet.190 THE ANALYST. The first principle of any sound undertaking was wholesome production, to avoid the necessity of sterilisation.He had had the honour of being connected with the Aylesbury Dairy Company for a great many years, and he thought he might say for it that its first element, and the basis of its whole organisation, was not sterilisation, but sound pro- duction. Some one had said that the two most dangerous drinks were milk and water, but there was nothing that was useful in nature that was not dangerous, and indeed there was no single act of life that mas not dangerous if it were abused. The first duty of those having charge of milk or dairies mas to see that there was no poison at the source. They had heard a great deal about the filtering of the Thames water, but that was after sewage had been introduced into it.They knew that it was the first duty of Parliament to prevent the introduction of pollution, and the Aylesbury Dairy Company had always acted on the idea that those whose duty it was to produce milk ought to present an article of sound, wholesome, and high quality. They had heard something of the standard of milk, and of the minimum standard. So long as they had a minimum standard, there would always be a commercial tendency to work down to it, but this Company had always considered it to be itsduty to work to the highest. All that they had heard that day about microbes, germs, and scarlet fever, was not to the point. He would not say that it was a simple waste of time, ag they were matters that had to be studied ; but in connection with this Company, the great duty it set before them was to put the cow under such conditions that from the cow (and including the cow) to the consumer, there should be no possibility of the introduction of germs.For that pur- pose they had to take a healthy cow, to keep it under healthy conditions, and to see that their receptacles and everything coming into contact with the milk were kept free from pollution. This done, they could well afford to leave the rest to the two departments of Government, who, he was sorry to see, instead of combining with each other in con- sultation, had appointed professors to fight with each other. He hoped that those who had joined in the inspection of the farm this day would see that there was a combina- tion of wealth and correct scientific knowledge, to produce milk which was distributed direct from the cow to the consumer, which required no sterilisation, and was perfectly free from all disease germs. It was the intention of the Company to have no diseased cows, and that should be the main object of every dairy company. Dr. J. F. J. SYKES (Medical Officer of Health, St. Pancras) also addrewed the meeting, and a vote of thanks was afterwards passed to Mr. Allender, on the motion of COLONEL the HON. W. P. TALBOT. After luncheon the company were taken to the calving farm, and to another farm, at which the pigs are kept, in every place much being seen worthy of admiration. This walk, some distance away from the principal homestead, Stammerham, afforded an oppor- tunity of seeing some of the corn and fodder crops and of the pastures j and an ascent of Sharpenhurst Hill revealed a charming panorama of a large part of Sussex. It was then time to take to the train, and a merry homeward journey brought to a close a most interesting, instructive, and enjoyable day. Corzclztsion of the Society's Proceedings,

ISSN:0003-2654    

DOI:10.1039/AN887120183b

出版商:RSC    

年代:1887

数据来源: RSC

摘要:

THE ANALYST. 191 ~ COMMUNICATION FROM THE SOUTH LONDON PUBLIC LABORATORY-- SIMPLE SUGGESTIONS FOR THE PURCHASE AND ASSAY OF COMMER- CIAL CaRBOLIC COMPOUNDS USED FOR SANITARY PURPOSES. BY JOHN MUTER, F.R.S.E., F.I.C., AND L. DE KONINGH, F.I.C. OWING to the extensive use of these compounds by the various local mnitary authorities throughout the country, and the occasional demands on the official analyst for their valua- tion, it is very desirable, both in the interests of the producers and the consumers, that there should be some simple and definite methods agreed upon for their analysis. Up till the present time we venture to think that if the same sample were sent toany dozen analysts, taken by chance all over Great Britain, not more than two or three would come within measurable distance of each other in the percentage of carbolic acid found, while it is more than probable that the manufacturer’s chemist would disagree with all.This state of things is caused :- (1) By the fact that, very probably, nearly all the operators would employ a pro- cess of their own devising, and that, although most would work upon similar lines, yet the details would be so different as to cause a very wide divergence in the finished results. (2) By the fact that, in commercial mixtures of carbolic acid and the higher phenols, the commonly adopted methods come entirely to grief. The process of Koppeschaar (although we continually meet with some one who has modified it so as to render it perfect) is totally unreliable for commercial use, because it is full of pit-falls.For example, to begin with, we have the necessity of working on Such small quantities that any experimental error is multiplied by something like 1,000 ; and then, as we are really to a great extent precipitating cresol and calculating it as phenol, we cannot on the face of such a fact expect much truth in the result. This is not, however, all, because the process is not to be depended upon even when dealing with pure medicinal acid. One may set to work to make a series of test experiments, and may theorise that, if it can only be arranged so that me work with the same excess of bromine and for the same time, ws are bound to get concordant results. If any one has SUC- ceeded in really carrying auch reasonable theory into practice without meeting with some unaccountable differences in the very first long series of experiments, then he has been much more lucky than we have ever been, and, so far as we know, we have tried every published modification, besides those resulting from our own experiments.Another thing which tends to lead to much dissatisfaction in such matters is the tendency of local authorities to contract wildly for powders or liquids “ contaGng (my) 15 per cent. carbolic acid,” without getting their medical officer to ask the analyst whether such an article really exists in commerce. The manufacturer takes such a contract with a light heart, because he knows that he can practically put in an acid as tarry and weak as he likes, and argue (if challenged) that he really put in 15 per cent.of “ commercial ” carbolic acid, and bring reliable witnesses, if needful, to prove they taw it done. Meantime the powder is complained of and sent to the analyst, who is asked to state the percentage of carbolic acid. He does this according to his lights, and naturally takes the words of the contract as literal, and reports the amount of real phenol he finds, This being generally microscopic, the authority becomes indignant, and192 THE ANALYST. the manufacturer, in defending himself as above shown, hints that the analyst is incom- petent, and generally gets one or two persons on the local board to believe him. If, in such matters, the boards could be induced to consult their analyst before issuing the form of tender, they would then learn that words like those we have above commented upon are absolutely useless in such cases, and that it is ridiculous to ask for a thing which never could be supplied in practice within any reasonable limit of cost.It may be now taken as a tolerably well admitted fact that, setting aside the necessities of surgery and medicine, the cresol and other higher phenols are just as good for ordinary antiseptic purposes as real carbolic acid itself, and that unless the presence of such congeners be permitted, the cost of disinfectants of this class mould be quite pro- hibitory. It is therefore sufficient that the analyst should see that his board is being supplied with an article which is all made up of mixed phenols, and not with tar oils, containing only a small proportion of such bodies.To ensure this the following, or some similar, form of tender should be employed : (( Commercial liquid carbolic acid at - per gallon. This article is not to be darker than pa10 sherry, and it is to contain not loss than 95 per cent. of carbolic and other allied acids obtained from tar, the said acids being in their liquefied form, but free from any excess of water. The said article to be subject to the approval of the Public Analyst (whose decision shall be final) on a sample drawn from each delivery by the Medical Officer. Such analysis is to be carried out and the result communicated to the contractor within six days after delivery of each consignment, and should the result be unfavourable the contractor shall remove the rejected article at his own charge.” Turning now t o carbolic powders, we may take it as also a fairly admitted pro- position that a commercial acid, such as has been above described, may justly be used in their manufacture, provided that the base of the powder is some siliceous matter, or gypsum, or native limestone, with none of which phenols will combine; but when such acid is employed the use of slaked or caustic limo should be rigorously tabooed.It has been proved that the antiseptic powers of cresol (for example) are entirely masked when combined with an alkali or alkaline earth, and what is true about this body is probably also correct about the other higher phenols present. Analysts looking after the interests of their district should advise a specification worded something like the following :- (( Carbolic powder, containing not less than 15 per cent.of the commercial carbolic acid as above described, and having for its base any siliceous or other inert mineral matter with which the acid will not combine. The use of quick or slaked lime as bases are specially to be avoided, and each consignment is to be subject to the same conditions of delivery and approval as in the case of the acid above described.” I n some cases a small supply of really pure liquefied carbolic acid is required, and then the simplest contract is for an article which shall correspond in every respect to acidurn carboliczcrn l i p factzcm of the British Pharmacopoeia. Such specifications are now in force in several of the districts served by this labora- tory, and since their adoption, together with the processes about to be described, there have been no disputes ; moreover, on the few occasions when a parcel had to be rejected, the manufacturer, on making inquiries, found that his own people had been in error, and at once admitted the mistake.THE ANALYST. 193 There is nothing more involved in the processes than the following well-known (1) Phenol, cresol, and their homologues are completely soluble when shaken up (2) Liquefied phenol and the corresponding cresol are insoluble in a saturated (3) In the presence of a sufficient excess of alkali, even a largely diluted solution (4) Tar oils and naphthaline are only very slightly dissolved by the alkali, and Taking these ltscertained facts, we apply them in the following manner, taking each data :- with a b per cent.solution of sodium hydrate. solution of sodium chloride. may be boiled down without the slightest appreciable loss of phenol or cresol. may be perfectly removed from the solution by agitating it with benzol. w e in turn :- (1) PBOCESS FOR THE VALUATION OF A CARBOLIC POWDER IN WHICH THE BASE IS NOT LIME, AND THE PHENOLS ARE CONSEQUENTLY NOT IN COMBINATION. Weigh out 100 grammes of the powder, and transfer the same to a flask, and add 400 C.C. of methylated spirit ; then, having introduced a well-fitting cork, agitate for a minute or two at intervals during an hour, and finally set the whole aside to settle. When subsidence is complete, pour or filter off 300 C.C. of the supernatant liquid, which thus represents 76 grammes of the original powder actually taken for analysis.Hereit may be noted that in laboratories fitted with the specially large “ Soxhlet ” apparatus required, a more rapid and economical method is to mix the original powder with bran, and to extract it in such an apparatus, with just sufficient spirit to do the necessary work. To the spirituous extract of the powder, obtained as above described, 200 C.C. of 6 per cent. solution of sodium hydrate are now added, and the mixed liquids are evapo- rated to about half their bulk. At this point any tar-oils or naphthaline present will separate out, and are to be removed by filtration. The filtrate, freed from these im- purities, is now evaporated down to a bulk not exceeding 50 c.c., and transferred to a specially constructed measuring tube surrounded by cold water, the basin being rinsed out with water, so that the entire amount of fluid in the tube shall be exactly 65 C.C.The tube employed is of peculiar form, capable of holding over 110 c.c., and is specially graduated and stoppered. It is wide at the base, and is narrowed at 65 C.C. from the bottom to such a diameter as to show, when graduated, -25 of a C.C. The first gradua- tion is at 20 C.C. from the bottom, the second at 65 c.c., and then the delicate gradua- tions (in -26 of a c.c.) commence and continue for 45 C.C. more up to 110 C.C. The tube is furnished with a long stirring rod made as thin as possible, and projecting above the tube to a convenient extent. [These tubes are to be procured from Mr. Cetti of Brooke Street, Holborn, who knows them as Muter’s carbolimeters,” and the entire apparatus costs 8s. 6d.l Before proceeding to use the tube for the first time, it is necessary to find the allowance to be made for the rod.This is done by Glling the tube with brine up to the 75 C.C. mark and then pouring in liquefied carbolic acid up to the 85 C.C. mark. The rod is now introduced and the amount of displace- ment it cauw noted, so that an equivalent allowance may be made on all future ex- periments. The measuring tube having been charged, as already described, we now proceed to194 THE ANALYST. add very cautiously, and with constant stirring 25 C.C. of strong hydrochloric acid, and when that is all in, we follow it with a teaspoonful of common salt. All the phenols now rise to the surface, and when the whole is at the temperature of 60Q Fah., the volume is read off, which gives the amount of commercial carbolic acid present in the 75 grammes of powder.I f a perfectly accurate result be required, it is necessary to remove some of the floating acid with a pipette, take its specific gravity, and correct the volume reading to weight. (2) MODIFICATION OF THE ABOVE PROCESS FOR USE WITH POWDERS ON A LIME BASE, WHERE THE ACIDS ARE COMBINED. Before proceeding with the spirit extraction, the weighed portion of the powder is to be treated in a capacious mortar with successive small quantities of diluted sulphuric acid (one in three) until the whole mass has a faintly acid reaction, and then the process applied BE( above described. It is necessary to be very particular about the treatment in the mortar, because, if the least particle of the powder escapes the action of the acid, the results are vitiated, while at the same time, any marked excess of acid should be avoided.Both pestle and spatula must be thoroughly used. (3) EXAMINATION OF A SAMPLE OF COMMERCIAL CARBOLIC ACID. case 1. The sample is dark in coZour.-Put some of the sample into the ‘‘ carboli- meter ” up to the 20 c . ~ . mark, then gently add 5 per cent. solution of sodium hydrate up to the 100 C.C. mark, and lastly add 10 C.C. of benzol. Put in the stopper, and having inverted the tube once or twice, plunge it into cold water. Repeat this shaking and cooling until the separation is complete. Read off the volume of the dark layer, which will now have formed beneath the 100 C.C.mark, and the amount of this will give the tar-oils, etc., present in the sample. Provided there is no excess of water, this amount is deducted from 20 c.c., and the difference multiplied by five gives the percentage strength of the sample. Excess of water (which is of very rare occurrence) is best ascertained by adding some of the sample to three times its volume of benzol, when it should dissolve quite clear if there bo no such excess. 2% sample is not darker than pale sherry.-Try if it dissolves nearly clear in four times its volume of 5 per cent. solution of sodium hydrate, and if so, it may be taken as practically free from tar-oils. If not, treat it as above, using however, only a very small fixed volume of the benzol.This acid is apt to contain excess of water, which must be estimated by shaking 20 C.C. of the sample in the “carbolimeter” with 80 C.C. of saturated solution of sodium chloride, and observing the diminution in volume that will take place if such excess be present. A fair idea tt9 to whether the acid is chiefly phenol or cresol may always be obtained by applying the bromine reaction, and observing the nature of the precipitate. Case 2. (4) EXAMINATION QF A SAMPLE OF PURE CARBOLIC ACID IN THE LIQUEFIED FORM* In examining samples of this acid, specific gravity practically goes for nothing. The points to determine are :-(1) That it should entirely dissolve to a perfectly clear solution in four times its volume of 5 per cent. solution of sodium hydrate ; (2) That, when shaken with an exoess of saturated solution of sodium chloride, as already described, it suffers no diminution in volume ; (3) When treated with bromine water in ~ x C ~ S S it gives a fine curdy precipitate, not at all inclined to stick to the tube.THE ANALYST. 195 I n conclusion, we can only repeat our statement that, if those persons engaged in the examination, and in the general supervision of carbolic antiseptics supplied to public authorities, would only agree to universally adopt some such simple methods and specifications as we have described, there would be universal satisfaction, instead of the dis- putes now so common, and, in addition to all that, the public money would be spent to infinitely better purpose than it now is in too many districts.We could name a t least one district in the Metropolis itself where the present fever epidemic is being fought with so-called ‘‘ carbolic acid,” which is practically all inerb tar-oils, and does not contain even 2 or 3 per cent. of the higher phenols, much less any real carbolic acid. It is time that local authorities consulted the public analysts more frequently before entering into such a purely chemical matter as a contract for carbolic articles. It is not to be expected that medical officers can keep such things in order, unless where (as in certain of our own districts) the knowledge of the chemical officer is called into play to check the con- tractors, and to advise as to forms of contract that can really be carried into practice with full justice to all parties concerned.

ISSN:0003-2654    

DOI:10.1039/AN8871200191

出版商:RSC    

年代:1887

数据来源: RSC

摘要:

THE ANALYST. 195 THE POLARISATION OF MILK. BY H. W. WILEY, CHEMIST TO THE U.S. DEPARTMENT OF AGRICULTURE. (Conclwded from page 181.) Iff.-COMPARISON OF RESULTS OBTAINED BY EXTRACTION WITH ALCOHOL AND POLARISA- TION. By consulting table No. 10 it will be seen that the percentage of sugar obtained by extraction with alcohol is practically the same as that got by polarisation of the lead acetate filtrate. Thus, the mean percentage of sugar by alcohol (65 analyses) is 4.32 ; by lead acetate, cold (53 analyses) is 4.34 ; by lead acetate, hot (64 analyses) is 4-38 ; by mercuric nitrate, cold (61 analyses) is 4-58; by mercuric nitrate, hot (24 analyses) is 4.63. If now the milk-sugar, as has already been intimated, exists in an anhydrous state after extraction with alcohol, the percentage of it after the addition of the molecule of water would be increased. Thus molecular weight of anhydrous milk-sugar, 342: molecular weight of the hydrous 360 =4*38 : x, whence the value of x = 4.61.This agrees very nearly with the number obtained by acid mercuric nitrate. By a study of table No. 13 it is found that the mercuric iodide gives nearly the same rotatory power as mercuric nitrate, and also by combustion the filtrates from the milks clarified by lead acetate contain more albumen than those prepared with mercuric iodide, There is, therefore, every reason for believing that the numbers given by the mercury salts are nearer the truth than those from the lead. It may be urged that the increased rotatory power observed by the mercury salts is due to the conversion of the dilute acids of a part of the lactose into galactose, which has a rotatory power greater than that of milk-sugar.But when it is remembered that the quantity of acid introduced is extremely minute, that the samples need not be warmed, that they can be filtered and polarised within a few minutes of the time of the intro- duction of the reagents, the suggestion is seen to be of no force.196 THE ANALYST. For example, in the acid mercuric nitrate it was found that the percentage of sugar was the same whether one, five, or ten cubic centimetres of the reagent were employed, and whether it was polarised immediately or after heating and cooling. It is evident that 1 C.C. of the reagent, containing less than a half cubic centimetre of nitric acid and diluted in 100 c,c, of liquid, could not exert any notable effect on the rotatory power of the solution.I n the mercuric iodide solution 20 C.C. of acetic acid are used for every 660 C.C. of the reagent. Thirty cubic centimetres of this reagent contain, therefore, about 1 C.C. of acid. This, in 100 C.C. of liquid, immediately filtered and polarised, could not affect in any marked degree the rotatory power. Since oombustion with soda-lime shows that the filtrate from the mercuric iodide sample is practically free from albumen, it is evident that the numbers obtained in this way must be a near approximation to the truth. IV.-THE PROCESS OF ANALYSIS. The reagents, apparatus, and manipulation necessary to give the most reliable results in milk-sugar estimation are as follows :- Reagents.-( 1 ) Basic plumbic acetate, specific gravity 1.9'7.Boil a saturated solu- tion of sugar of lead with an excess of litharge, and make it of the strength indicated above. One cubic oentimetre of this will precipitate the albumens in 50 C.C. to 60 C.C. of milk. ( 2 ) Acid mercuric &itrate; dissolve mercury in double its weight of nitric acid, specific gravity 1.42. Add to the solution an equal volume of water. One cubic centi- metre of this reagent is sufficient for the quantity of milk mentioned above. Larger quantities can be used without affecting the results of polarisation. ( 3 ) Mercuric iodide with acetic acid (composition already given). Apparntzcs.-(l) Pipettes marked at 59.5 c.c., 60 c.c., and 60.5 C.C. ( 5 ) Thermometers.(2) Sugar (4) Specific flasks, marked a t 102.4 C.C. gravity spindle and cylinder. (3) Filters, observation tubes, and polariscope. V.-MANIPULATION. ( 1 ) The room and milk should be kept at a constant temperature. It is not im- The work can be carried on The slight variations in rotary power within The temperature For general work this is done by a Where greater accuracy is required we specific gravity ( 3 ) If the specific gravity bs 1.026, or nearly so, measure out 60.5 C.C. into the Add 1 c.c, of mercuric nitrate solution, or 30 C.C. mercuric iodide solution, The precipitated albumen occupies a volume of about 2.4 C.C. If the specific gravity is 1.030, use 60c.c. of portant that the temperature should be any given degree. equally well at 15* C., 20° C., or Xi9 C.the above limits will not affect tho result for analytical purposes. selected should be the one which is most easily kept constant. delicate specific gravity spindle. flask. sugar flask. and fill to 102.4 C.C. mark. Hence, the milk solution is really 100 C.C. milk. ( 2 ) The specific gravity of milk is determined. I f the specific gravity is 1.034, use 59.5 C.C. of milk. ( 4 ) Fill up to mark in 102.4 c.c, flask, shake well, filter, and polarise.THE ANALYST 197 VI.-NOTES. In the above method of analysis the specific rotatory power of milk-sugar is taken at 52.5, and the weight of it in 100 C.C. solution to read 100 degrees in the cane-sugar scale at 20.56 grammes. This is for instruments requiring 16-19 grammes sucrose to produce a rotation of 100 sugar degrees. It will be easy to calculate the number for milk-sugar whatever instrument is employed. Since the quality of milk taken is three times 20.56 grammes, the polariscopic readings divided by 3 give a t once the percentage of milk-sugar when a 200 m.m. tube is used. If R 400 m.m. tube is employed, divide reading by 6 ; if a 500 m.m. tube is used, divide by 7.5. Since it requires but little more time, it is advisable to make the analysis in dupli- a t e , and take four readings for each tube. By following this method gross errors of observation are detected and avoided. By using a flask graduated at 102.4 for 60 C.C. no correction for volume of precipi- tated casein need be made. I n no case is it necessary to heat the sample before polarising.

ISSN:0003-2654    

DOI:10.1039/AN8871200195

出版商:RSC    

年代:1887

数据来源: RSC

摘要:

THE ANALYST 197 A NEW PROCESS FOR THE SEPARATION OF THE OPIUM ALKALOIDS. WHILST we are in possession of accurate processes for the separation of the cinchona alkaloids, unfortunately this is not the case with those of opium, and I have therefore endeavoured to find those reagents most suitable for the separation of the latter. As the result of numerous experiments I now use for the separation of the six most impor- tant alkaloids (narcotine, papaverine, narceine, thebaine, codeine, and morphine) the following reagents : sodic acetate, potassic ferricyanide, sodic salicylate, potassic sulpho- cyanate, and ammonia. BY PROFESSOR DR. P. C. PLUGGE. (a;) SEPARATION OF NARCOTINE AND PAPAVERINE FROM THE OTHERS. To carry this out I use sodic acetate. As I have already communicated in a previous paper, strong solutions of morphine, codeine, and thebaine, are not precipitated by this reagent.Narceine is precipitated from concentrated solutions, but no longer if the per- centage does not exceed 016. But papaverine is thrown down from a very weak solution (1-30,000), and narcotine from a still weaker one (1 - 40,000). Sodic acetate will there- fore eliminate the two last alkaloids, and there is no danger of narceine co-precipitating if the fluid is only sufficiently diluted. The alkaloids precipitate as such in a pure state. After having tried various means to separate the precipitate a I thought potassic ferricyanide would answer best. The two alkaloids are very di6cult to separate, as they behave slimilarly towards most reagents, and they even do so apparently when treated with the ferricyanide.If, however, the solution contains no more than -25 per cent. or less, the narcotine is no longer precipitated, whilst papaverine is still thrown down from solutions containing 1 -3@00. Even solutions containing only 1-4,000 &ill yield a yel- lowish precipitahe after some time, It is therefore pl& that if the precipitateobtained (6) SEPARATION OF THE NARCOTINE AND PAPAVERINE.108 THE ANALYST. by sodic acetate is dissolved in just sufficient dilute hydrochloric acid, and then diluted to such an extent as to contain no more than *25 per cent,, the addition of potassic ferri- cyanide will only precipitate the papaverine. If, after standing for twenty-four hours, the liquid is filtered, the filtrate will contain all the narcsine, which can be obtained as pure alkaloid by addition of ammonia. The precipitate consists of hydroferricyanate of papaverine, which may be weighed as such, but which for qualitative purposes is con- veniently made into the pure alkaloid by digesting with a weak soda ley or dilute ammonia.To make absoiutely sure, the isolated alkaloid may be redissolved in weak hydrochloric acid and once more precipitated with ammonia. (C) SEPARATION OF NARCEINE. After filtering off the fluid a we have in solution, besides the excess of sodic acetate, thebaine, codeine, and morphine, also the narceine. To recover the latter it is sufficient t o concentrate the fluid on a water-bath, and when at last the liquid contains more than -16 per cent. the excess will crystallise out on allowing to cool.The precipitation is, of course, incomplete, and depends on the degree of concentration. (d) SEPARATION OF THEBAINE. I now make use of a strong solution of sodic salicylate, to remove the thebaine. The liquid contains, besides this alkaloid, narceine, codeine, and morphine. Thebaine salicylate is very insoluble, as solutions of thebaine containing no more than 1-2,OOO are still precipitated by the reagent. After standing from twenty-four to forty-eight hours the deposit is filtered off and washed. For quan- titative purposes it may be weighed as pure thebaine salicylate after drying at 1000 C. ; but for the purpose of testing, the pure alkaloid must be isolated by digesting the com- pound with weak soda, ley until every trace of salicylic acid is removed.(e) REMOVAL OF THE EXCESS OF SODIC SALICYLATE AND THE TRACES OF NARCEINE AND The filtrate from d contains, besides codeine and morphine, small quantities of narceine and traces of thebaine, and also excess of sodic salicylate, which must be removed before we can estimate the two first. I therefore add dilute hydrochloric acid, and after some little time filter off from the salicylic acid. The filtrate is now shaken out with chloroform, which removes the last traces of salicylic acid, also the narceine and thebaine, whilst codeine and morphine are not dissolved. I must warn against using too much hydrochloric acid, so that a little sodic acetate may still be left undecomposed. I f the liquid contains free hydrochloric acid, chloroform will not properly extract the narceine and thebaine.The other alkaloids are not affected. THEBAINE. (f) SEPARATION OF CODEINE. The liquid is now gently heated to expel any chloroform, and after being some- what concentrated, mixed with a solution of potassic sulphocyanate, which throws down the codeine. Previous experiments with the hydrochlorates of morphine and codeine had shown me that even a 4 per cent. solution of the former gives no turbidity with the reagent, but the latter is readily precipitated in the cold from its 95 per cent, solution. Even solutions containing only -1’7 per cent. still yield small crystals of codeine hydro- sulphocyanate after being left in contact with the reagent for forty-eight hours. SoTHE ANALYST. 199 ~ ~~ with care it is easy to practically separate the codeine, leaving all the morphine in solution.(9) SEPARATION OF THE MORPHINE. The filtrate from f is now mixed with a little ammonia, and allowed to stand in an open beaker till the excess of ammonia is practically evaporated. The greater part of the morphine crystallises out, and may then be collected. The little codeine still remaining is not precipitated. As, however, the liquid retains a not inconsiderable amount of morphine, the following process will be found more accurate for quantitative purposes, especially when working on small quantities of alkaloids. The liquid is rendered alkaline by ammonia, and after standing at rest for some time in a separating funnel, repeatedly shaken with either chloroform or ether, which will remove the codeine, but not the morphine.The liquid is now acidified with hydro- chloric acid (to redissolve the morphine), then heated to about 60°C., and repeatedly shaken out with amylic-alcohoI, after addition of slight excess of ammonia. How far the proces suits quantitative analysis I wish to show by the following test analyses. 1. ESTIMATION OF NARCOTINE IN THE PRESENCE OF MORPHINE. 10 C.C. of a solution containing *1354 grm. of narcotine, and 011516 grm. of Precipitate morphine, were mixed with 5 C.C. of 10 per cent. solution of sodic acetate. meigbed -1315 grm. = 97.12 per cent. narcotine recovered. I n two other experiments respectiveIy 100 and 97.5 per cent. were obtained. 2. ESTIMATION OF NARCOTINE IN PRESENCE OF OTHER ALKALOIDS. 50 c.c., containing 98612 narcotine, -1027 morphine, 01228 codeine, and 01544 thebaine.Sodic acetate precipitated -2845 grm. of narmtine, or 99.43 per cent. 3. ESTIMATION OF PAPAVERINE IN PRESENCE OF MORPHINE AND OTHER BASES. 40 C.C. of a solution containing -28635 grm. of papaverine and *1415 of morphine 50 c.c., containing *3247 papaverine, -0638 morphine, 01319 codeine, and 00915 yielded with sodic acetate 0281 grm. = 98.15 per cent. papaverine. thebaine, obtained 0315 grm. papaverine = 97-02 per cent. recovered. 4. ESTIMATION OF PAPAVERINE BY PRECIPITATION AS HYDROFERRICYANATE. *181 grm. hydrochlorate of papaverine yielded with potassic ferricyanide a precipi- It ought to have weighed 019795 grm. ; therefore 97.5 por tate weighing 0193 grm. cent. recovered. 5. ESTIMATION OF THEBAINE AS SALICYLATE.From a mixture of this alkaloid with papaverine, morphine, and codeine, I suc- ceeded in recovering 90 per cent, of the thebaine. 6. ESTIMATION OF CODEINE AS HYDROSULPHOCYANATE. -35 grm. of hydrochlorate of codeine were dissolved in about 50 C.C. of water, and After standing for twenty-four hours the precipitate Its weight amounted to *253 grm. But after concentrating and allowing mixed with 5 c.c, of the reagent. was filtered off, and collected, on a weighed filter. corresponding with 02113 grm. of pure codeine.300 TEE ANALYST, to stand for another twenty-four hours, a further precipitate was obtained, weighing *082 grm., which brings the amount of codeine recovered, up to 97.55 per cent. 7. ESTIMATION OF CODEINE IN PRESENCE OF MORPHINE. Cam must be t&en not to have thesolution too strong, otherwise there is a danger of morphine hydrosulphocyanate crystallieing out. *20643 grm, of codeine and *271 grm. of morphine (as hydrochlorates) were dissolved in 15 C.C. of water, and mixed with 2 C.C. of the reagent. I obtained 101.14 per cent. codeine, plainly showing oontamina- tion with morphine. Further experimenb Bhowed it is not possible to leave all the morphine in solution without suffering a considerable deficiency of codeine. I could in fact only recover about 70 per cent. of the latter.

ISSN:0003-2654    

DOI:10.1039/AN8871200197

出版商:RSC    

年代:1887

数据来源: RSC

摘要:

300 THE mALYST. SIONTHLY RECORD OF ANALYTICAL RESEARCHES INTO FOOD. THE DETECTION OF FAHLBERGI’S SACCHARIN. c . SCHMITT. Reperf. Anal. Chemie, SO.-!I!o detect the presence of this substance (ortho-sulphamido-benzoic acid) in wine, the author recommends the following method:-100 C.C. of wine are acidified with sulphuric acid, and well shaken in a separating funnel, with 50 C.C. of a mixture ol equal volumes of ether and petroleum spirit. The mixed ethereal liquids are evaporated in a silver or porcelain dish with a few c.c.of soda ley, and when dry, the residue is heated for half an hour in the air bath up to 2509 C. The fused mass is then dissolved in water and tested for saZkyZic acid by acidifying with dilute sulphuric acid, shaking with ether, evaporating the latter, and adding a drop of ferric chloride to the residue.This process is based on the fact that Fahlberg’s saccharin yields sodic dicylate on fusing with sodio hydrate. The process gets more complicated when salioylic acid has been added to the wine as a preservative. The extraction is twice repeated. L. DE K. TEST FOR ANILINE COLOURS IN WINES OR FBUIT JUICES. C. 0. CURTMAN. Zeitschr. f. Anal. Chemie, H. 4.-Aniline colours are often used to colour diluted wines or artificial fruit juices, jams, etc. The.author uses for their detection, Hofmann’s well- known isonitril test. 4 C.C. of wine were coloured with fuchsin, and then mixed with 4 C.C. of potash ley, and 2 drops of chloroform. After first gently warming for a minute and subsequent boiling, the chamteristic smell of isonitril was plainly perceptible.The sulpho compound of rosanilin gave the reaction only after some time. The test may be rendered more delicate, on finally adding some sulphuric acid. The small quantities of compound ethers present in the wine do not interfere with the delicacy of the test. The teat ww also successful with aniline blue, aniline purple, aniline violet, magenta, and ponceau red, and many yellow and green milines. L. DE K. THB REFBACTOMETER IN BEER ANALYSIS. SCHWARZ. Nordd. Braaer Ztg., 973.- m e author gives a method for determining the ariginal gravity of beer, based on theTHE ANALYST. 201 ~~ ~ ~- following principles :-The gravity of beer is dependent on the amount of alcohol, which lowers it, and the amount of extract, which increases it. One per cent. of extract increases the gravity 000395 degree, whilst 1 per cent. of alcohol lowers it by -00161 degree. Now if any beer has a gravity of 1*02122, we will have as the first equation 395 x- 161 y = 2122. On applying the refractometer, 1 per cent. of solid matter increases the deviation by *00150 degree, and 1 per cent. of alcohol further increases it by *00062 degree. Now if the sample shows a deviation of 1.01250, we get as second equation 150 x + 62 y = 1250. The value of x and y can now be readily calculated, and from their amount the original gravity is x represents the extract, y the alcohol. ascertained as usual. L. DE I(.

ISSN:0003-2654    

DOI:10.1039/AN8871200200

出版商:RSC    

年代:1887

数据来源: RSC

摘要:

THE ANALYST. 20 1 MONTHLY RECORD OF ANALYTICAL RESEARCHES INTO DRUGS. Repert. Anal. Chemie, No. 34.- A sample of fat mixture submitted to the author for analysis, apparently contained wax. On investigation it proved to have an acidity equivalent of 52, a saponification ditto of 118.5, an ether ditto of 66.5, and the relation of acidity to ether equivalent as 1 : 1.28, Pure beeswax gives the following numbers : 20, 95, 75, 3.75. Paraffin could, therefore, not be present, but there might be a mixture of stearic acid, tallow, or rosin, or only one of these bodies. When treated according to the prdcess recommended by Benedikt and Zsigmondy, no glycerine was found, proving the absence of tallow. The low ether equivalent practically excluded stearic acid, and rosin was therefore the only pro- bable adulterant.To qualitatively test for rosin, the author first macerated with alcohol, which dissolves the rosin and takes up but little wax. The residue left on evaporation was now treated according to the process recommended by Donatb, which consists in first boiling with nitric acid, then diluting with water, and finally adding excess of ammonia, when a blood-red colour conclusively showed the presence of rosin. The fusing point and the specific gravity were as might be expected higher than those of pure wm. ESTINATION OF ROSIN IN WAX. F. M. HORN. The percentage of rosin was now calculated from the formula- 100 : R = (146 - 20) : (63 - 20) R = ST 26.4 The figure 146 represents the acidify equivalent of rosin (colophony). A very satisfactory result was obtained bytesting a made-up mixture of 75 parts of wax and 26 parts of rosin.L. DE K. MONTHLY RECORD OF GENERAL RESEARCHES IN ANALYTICAL CHEMISTRY. Zeitschr. f. Anal. Chemie. H 4. -To see whether indigo has been r d y used, the author tests the goods as follows: Boiling water or warm alcohol of 96 per cent. should not extract any colour. No colour should be TESTING FOR INDIGO. W. LENZ.202 T-HE ANALYST. dissolved by boiling with saturated solutions of oxalic acid or borax. When treated with the latter, no red colour should be obtained on acidifying with hydrochloric acid, and subsequent addition of ferric chloride should not turn it blue. The goods should not be affected on boiling with a 10 per cent. solution of alum, or a 33.3 per cent. solution of ammonium molybdate. A mixture of stannous and ferric chlorides in equivalent proportions should completely destroy the colour on warming. The colour should be completely soluble in boiling glacial acetic acid. On adding to this solution, first double the volume of ether and then some water, the bulk of the colouring matter should float between the two layers. The ether should be but faintly coloured, and the acid be perfectly colourless, and remain so on adding a little hydrochloric acid. . The dye should not yield any sulphuretted hydrogen on boiling with hydrochloric acid, and no smell of isonitril on heating with caustic potash and chloroform. L. DE K.

ISSN:0003-2654    

DOI:10.1039/AN8871200201

出版商:RSC    

年代:1887

数据来源: RSC

摘要:

202 T-HE ANALYST. NOTICE TO CORRESPONDENTS. ALL Communications on Literary or Exchange Matters to be sent to 326, Kennington Road, London, S.E. “ Public Analyst ” would be much obliged to any of his colleagues who can give him particulars of any case that has occurred where an appointed analyst has had to enforce payment of his salary and fees against any local authority, or to resist an arbitrary reduction of the same by suing for the agreed amount. Particulars will be held in strict confidence (if so desired), and may be directed to the Editor of the ANALYST, 326, Kennington Road, London, S.E., and endorsed outside, ‘‘ Reply to Public Analyst,” when they will be duly forwarded,

ISSN:0003-2654    

DOI:10.1039/AN887120202b

出版商:RSC    

年代:1887

数据来源: RSC