PROCEEDINGS OF THE SOCIETY OF PUBLIC ANALYSTS. A GENERAL meeting of the Society was held on the 10th ult. at Burlington House. On the ballot papers being opened, it was announced that the following gentleman had been elected as a member :-Mr. W. J. Dibdin, F.I.C., F.C.S., London. The PRESIDENT said that it was only fitting he should refer to the recent death of Mons. Chevreul, who was an hon. member of their Society. Some years ago he had sent them a letter wishing the Society every success, and he was sure they would all regret his loss. Mr. Allen also made some remarks in allusion to the same subject. The following papers were read and discussed : "Contributions to the Study of the Action of Water on Lead Pipes," by A. H. Allen. "Iodine Absorption of Butter Fat," by Rowland Williams. "Pure' Chemicals," by Bertram Blount. "Some Experiments on the Soap Test," by Dr. E. Waller. The next meeting of the Society will be held at Burlington House on Wednesda y the 8th May inst. NOTES ON LACTOSE. By E. W. T. JONES, F.I.C. (Read at the Meeting, March 1889.) ABOUT twelve months ago I carefully purified some milk-sugar, and subsequently obtained some very nice crystals, which after draining, etc., were finally dried in vacuo over H.SO. The following notes of the results obtained with them I have every confidence in publishing, and although I do not propose to give all the experiments in detail, the results may be taken as very carefully fixed by repeated experiments. 5 grms. (exactly) of the crystals (=4.75 grms. anhydrous lactose) were put into a correct 100 c.c. flask, about 80 c.c, distilled water added, and solution effected by heating in boiling water for twenty minutes to half an hour. The next day the flask was filled up at 60° F. to exactly 100 c.c. Thus I avoided bi-rotation. The sp. gr. at 60° F. of such a solution is 1018-6, hence at this concentration the divisor for sp. gr. above 1,000 to get grms. per 100 c.c. of Using a Soleil-Ventzke-Scheibler polariscope, I find at this concentration the sp. rot. pr. for 54.6[a]p 51.9" Cupric reducing power with Fehling solution, using not less than 30 c.c. (diluted with two volumes of water) for 0.1 grm. lactose, heated in vessel surrounded by boiling water for fifteen minutes (O'Sullivan's method). I weigh as CuO, i.e., I convert the CuO into CuO by ignition in a porcelain crucible -the whole secret of sure complete oxidation being to use at first a very small flame to just char and destroy the filter paper, after which more heat may be applied and final ignition over the blow-pipe resorted to-proceeding thus the CuO does not cohere, and there is not the slightest risk about not obtaining full oxidation by ignition aloneduplicates should not, and generally do not, in my hands, differ more than a milligram. Action of citric acid.—I have corroborated that lactose is not affected optically, nor in cupric reducing power, by this acid, when proceeding as follows, whilst cane-sugar is completely inverted under such circumstances. Crystallised citric acid is added at the rate of 16 grms. per 100 c.c. of solution. Generally I take 50 c.c. of sugar solution and add 0.8 grm. of citric acid, and heat in 100 c.c. flask in boiling water for thirty minutes, and then make up to within half a grm. of the original weight. During the heating a little more loss in volume occurs by evaporation than the increase caused by the citric acid. The weight of the flask, solution and acid being taken before heating, and afterwards made with distilled water to within 1 grm. for 16 grm. citric acid, or within half a gramme for 0.8 grm. citric acid, exactly the same volume is obtained after treatment with acid as before, and, therefore, if only lactose is present, the polariscopic readings will be the same. 100 The proportion of citric acid recommended increases the bulk of the solution 1th, viz., 16 grms. citric acid to 100 c.c. makes it 101 c.c., and 0.8 grm. to 50 makes it 50.5 c.c., hence we arrive at the proper allowance for adjusting the solution to the original volume. I have said that cane sugar is completely inverted, and may I be pardoned for mentioning here that although the real sp. rot. pr. of invert sugar is, 23·75[a],, i.e., calculated on the increased molecule of the original cane-sugar, if calculated on the canesugar, as generally will be the case in practical work, 25.0 must be used. Crystals of lactose do not lose their water of crystallisation by twenty-four hours' heating in a water oven, but if the crystals be just dissolved in water and evaporated over a water bath to dryness, and then dried in the water oven for a few hours, anhydrous lactose is obtained; but the drying must be continued till the weight is constant, which proceeds slowly if the residue is thick. It has been stated that our residues containing lactose after drying in the water oven contain this body in the hydrated state, but this I dispute, if drying is conducted till constant weight occurs. 2:3810 grms. of the crystals after drying for twenty-four hours in the water oven, weighed 2.3806, practically no loss. 0-6828 grm. crystals just dissolved by addition of distilled water, then evaporated to dryness, after drying four or five hours in the water oven, became constant at 0-6500 grm. against 0.6487, the correct amount of anhydrous lactose corresponding to the crystals taken. It is quite needless for me to point out the practical application of these results in such analyses as those of condensed milk, etc., etc. COLOURING MATTER (ARSENICAL) USED FOR COLOURING CANDLES. BY W. F. LOWE, F.I.C., F.C.S., ASSOCIATE OF THE ROYAL SCHOOL OF MINES. (Read at the Meeting, March, 1889.) WHILST the use of dangerous mineral colours for colouring tinned and bottled fruits, wall papers, etc., has been pretty nearly stamped out, their use for colouring wax candles appears to have been overlooked. The danger of using them for such a purpose has recently been brought to my notice, and a brief description may be of interest to the members of our Society. A children's party was given by a gentleman in the district for which I am Public Analyst, and a Christmas-tree with a large number of small coloured candles was the principal attraction. On the day following the party about twenty per cent. of the children who had been present, and also several grown-up persons, suffered from symptoms of irritant poisoning. At first it was naturally supposed that something in the food had caused the mischief; but on making inquiries the gentleman found that some of those attacked had taken nothing to eat or drink in the house, but had been present at the Christmas-tree, so that it could not possibly be the food. His suspicions then fell on the green candles which had been used for lighting the tree, and as he had had a chemical training, he examined one of the green candles himself, and found traces of arsenic in it. He then forwarded the remainder to me for examination, and I found the green ones contained both copper and arsenic, evidently having been coloured with one of the arsenical greens, which appeared to be "emerald green." There was not sufficient material to estimate with any accuracy the amount present, but I was able to separate a small quantity of the colouring matter itself by dissolving the wax in warm ether. It is well to note that at first it appears as if the colouring matter had also dissolved, for it is in such a finely divided state that it floats about in the ether for some time, thus giving the appearance of a green solution; but if it is filtered or allowed to stand a few hours it is seen that it is merely in suspension. From information I have obtained, it appears to be a common practice in the smaller candle works to use arsenical greens for colouring candles, as they are easier to use than the aniline green, and stand the action of light so much better, the candles coloured with aniline greens having a tendency to fade unless kept in a dark place. The quantity employed, I am informed, is from oz. to over 1 oz. of emerald green to 28 lbs, of wax, and that for the small green candles about 1 oz. to 28 lbs, would be employed. At this rate each small candle, I find, would contain about grain of colouring matter, and would be capable of yielding aboutgr. of arsenious anhydride; so that I should say that a dozen or two of such candles burnt in a room of moderate size would be capable of producing very serious effects. Red candles also are usually coloured with an injurious mineral colour, at least for such a purpose, for vermilion is used, and a red candle from the same Christmas-tree, I find contains vermilion, but I believe the candles used were chiefly green ones. I intend to make a further examination of the matter, and I hope some of the other members will do the same, for I think that such a practice should, if possible be stopped. DISCUSSION. Mr. HEBNER said that about twelve years ago he was just about to publish a note on the same subject when he found that Prof. Church had already drawn attention to the matter. Mr. CASSAL said that the fact of arsenic having been found in candles was not new. Some years ago the question had been brought forward, and it was alleged that some people had been actually poisoned by arsenical candles, but if he recollected rightly they were white candles, not coloured ones. The subject was of very considerable interest and importance from a hygienic point of view. The statements that the practice was being stamped out he could not agree with. Most analysts still had a good many things to examine for the presence of arsenic. Some years ago, at the time of the Health Exhibition, he had occasion to examine a number of articles for arsenical and other poisonous pigments, among them butterfly nets, coloured balls, and various children's toys, arsenic in large amount being frequently found. The green gauze used for nets had been found to contain arsenic. The point was the extreme minuteness of the quantity by which the injury may come about. It would be a good case to help Mr. Dyer, as the whole chain of evidence was complete. With regard to the use of arsenious acid in candles, he understood it was used to give the burning wick the turn; and if that were so, he was surprised some evil effect had not been discovered. As to the rash mentioned, that was quite a fact; he had heard of several instances of rash being produced by arsenical pigments, which have an irritating effect on the skin. The whole matter was very interesting to him from a medical as well as chemical point of view, with the experience he had had. Mr. ALLEN said that the paper just read showed the desirability of extending the Sale of Food and Drugs Act. Public analysts ought to have under their care all such articles as arsenical wall-papers, fabrics of candles, besides disinfecting powders, &c. The subject was not strictly a novel one, but it was only by calling attention to cases which came within their own experience that it was brought home to them, and he thought they were indebted to the author for bringing the matter forward. He might remind them of the historical case of a member of the royal family of Austria who was practised on by introducing arsenic into the candles used in his bedroom. It was not fair to judge of the poisonous effects of arsenical paper or candles from the amount of arsenic present, for the finely-divided arsenious oxide would be so distributed through the atmosphere as to affect the system far more strongly than if an equal amount had been taken into the stomach; in fact, the effects would probably be more properly comparable with those attending the breathing of arseniuretted hydrogen, which was known to be intensely poisonous. He should like to know what became of the copper in the candles. How any candle could contain a measurable or weighable amount of copper which did not go into the wick he could not understand; in fact, if he had had to analyse such a candle, he thonght he should have burned the candle and condensed the arsenic by some contrivance similar to that for estimating sulphur in coal gas, and should have looked in the candle end for the whole of the copper which had been previously distributed throughout the candle. Mr. BERNARD DYER said he would be glad if Mr. Harvey would send him the medical details of the case. It might be known to members that this question of injurious colouring matters, not only applied as to papers, but to other things, had been taken up at various times by various societies, but more especially by the National Health Society. The Society of Arts had previously collected evidence and made a report, but nothing came of it. The National Health Society, in 1883, appointed a committee consisting of medical men and chemists to draft a Bill for the suppression of the sale of arsenical wall paper, on the same lines as the Acts of Parliament in operation on the Continent and, he believed, also in America. In Germany, he believed, arsenical paper was made and exported to this country, but it could not be sold in Germany. In Sweden there was a very stringent law on the subject. The great difficulty in drafting a Bill was in defining the word "arsenical." After considering the question for some time, Mr. Carr, Mr. Heisch, and Dr. Bartlett suggested a very excellent modification of the Marsh apparatus which seemed to meet all difficulties, both as to testing and defining arsenical colours. Dr. Willoughby was at first secretary of the committee, and was succeeded by himself (Mr. Dyer), and the Bill became finally matured during his (Mr. Dyer's) secretaryship, in 1885; and Dr. Cameron undertook to bring the matter before the House of Commons. But the Irish question came up, and Dr. Cameron said it would be perfectly hopeless to bring this forward then, as it would certainly be opposed by the large trade interests, and as he, moreover, was very busy; so nothing was done, and the draft Bill was still on the shelf awaiting an introducer and an opportunity of introduction. The fact remained that England is almost the only civilised country where arsenic-dyed wall papers were allowed to be sold. One of the great difficulties Dr. Cameron said they would have to contend with was that, as large trade interests were involved, and there would be much opposition, a Select Committee would be doubtless appointed, and that Committee would ask them for their medical evidence. Now, the Society of Arts and the National Health Society had gathered a drawer full of medical evidence, but much of it related to cases where the arsenic was so abundant that, on wiping the paper with a duster, the green came off on the cloth, and much more to cases where patients being out of health, and wall paper being found arsenical, the two facts were assumed to be cause and effect on grounds which, though very strong, did not afford strictly accurate and convincing evidence. They felt that, before the matter could be brought forward with full confidence, they should strengthen their medical evidence. Any strictly authentic cases of domestic poisoning from arsenic he should be glad to receive on behalf of the National Health Society, that he might hand them to Mr. Kenneth Millican, who had undertaken the collection and collation of medical facts on the question. Mr. CASSAL said that general practitioners among medical men who had not studied hygiene were not likely to give specially valuable opinions on the points referred toat least, that was his experience, which was not a small one. Mr. Cassal mentioned the case of a lady who had been wearing a bonnet with bronzed leaves in it, some of these leaves having been kept in close contact with the skin. The leaves contained a large |