112 THE ANALYST. INSTITUTE OF CHEMISTRY. WE have received the reports of the discussions which took place on 27th February and 2nd April, on the subject of the Adulteration of Food. We believe this is the first work, partaking in any degree of a scientific character, which has been undertaken by the Institute since its formation ; and it would, therefore, be hardly just to criticise the matter as closely a6 the proceedings of an older society, and the more so because by reason of the mistaken preference which the Institute has shown for secret meetings, and the iigid exclusion of visitors, several chemists who could have given really useful information were unable to be present.We suppose that this rule will be relaxed in future, since it seems improbable that the Council will exclude visitors from he&g what they can afterwards read, unless indeed the accommodation should prove to be too limited for the members attending. This, liowever, seems unlikely.The discussion was opened by Dr. Voelcker, whose speech extends to some thirteen pages; we can, therefore, only briefly notioe some of its salient points. Dr. Voelcker said there was no difficulty in determining ig whether milk had been adulteratedwith a considerable quantity-say 20 per cent.-of water, or whether skimmed milk had been sold as fresh.” h cases of that kind, the chemical or microscopical examination of the articles in question decides, with certainty, whether they are genuine or adulterated.” This, however, hardly accords with a statement a few lines lower.I need hardly aay that it is now admitted by all personn who possess some knowledge of dairy matters that the composition of equally genuine samples of milk varies greatly.” The speaker then went on to refer to his old milk experiments at Cirenoester, in 1863, and again quoted his analyses of the milk from the half-starved cows, bringing the produce of these wretched animals forward to show how variable milk is.He then referred to the limits laid down some years ago by the Society of Public Analysts, oalling them, however, by the erroneous name of standards.” After acknowledging that some analysts, ‘‘ no doubt very young and inexperienced,” had challenged the accuracy of his analyses, he said that the L L best informed ” of his opponents had altered their views on the milk question, and come round to his own.After a well-deserved passing sneer at half-crown milk analysts, Dr. Voelcker stated that he objected in toto to all milk standards, and characterised the present one as iLsomewhat low,” Four pages of the report are then occupied with a reprint of part of an oldTHE ANALYST. 118 paper on the importance of the hydrometer for determining the adulteration of milk, and mother page with an old paper on cream.Dr. Voelcker, carefully avoiding making any remarks which were capable of criticism in reference to butter, bread, tea, coffee, cocoa, or arrowroot, referred to the well-known selenite water used in making the Worcester vinegar ; and then passing rapidly over colouring matters, metallic poisons, salicylic acid, and spirits, concluded by pointing out what in his view was the absurdity of fining R man for 80 grains of salt per gallon in beer, The President (Dr.Frankland) followed with a few remarks, of which the most novel was the statement that, in taking the specific gravity of milk, the quantity of h t present would exercise no influence on the indications of the lactometer.” Dr.Dupr6 pointed out the error into which Dr. Voelcker had fallen, in calling the limits fixed by the Society of Public Analysts (‘ standards,” and remarked on the special attention which had been paid to these limits in Germany as compared with the consideration they had received in England. Referring to the milk question, he remarked that milk from under-fed cows was certainly not of the nature, quality, and substance demanded, He considered that Dr.Voelcker’s analyses of the milk of such cows had done much harm. In reference to alumina in bread he considered it impossible to lay down a proper limit, except by the comparison of the silica with the alumina present. He pointed out that in the case of flour it was easy to determine the alum by means of his process, already published in THE ANALYST.Referring to butter, Dr. Dupr6 again pointed out the fallacious inferences which may be dram from the sp. gr. only, when mutton fat has been used as an adulterant, and urged the necessity of the determination of both insoluble and soluble acids. With reference to the fines inflicted by some magistrates lie remarked that, by the addition of only 10 per cent.of water to the milk consumed in London, the sum of &150,000 a year would be paid for water. He concluded with a few observations as to the changes which may take place in drugs by long keeping. Dr, Stevenson regretted that Dr. Voelcker’s paper referred to so few subjects, and introduced so little new matter ; he believed that Public Analysts as a body were as trustworthy as the members of any other profession.He thought it would have been well had Dr. Voelcker’s analyses been made by modern methods instead of by methods now soarcely ever adopted by analysts, and considered that the milk of f&irly-fed cows did not present that wide difference which they had heard of that evening. Dr. Redwood thoughatthat spirits should be kept within certain limits, in order to justify the application to them of their popular names.He appeared to think that SO U.P. was a fair and proper strength-for gin, and that lower than that should not be allotred. He justified the addition of annatto to butter and cheese for the purpose of colouring them, but condemned the colouring of pickles with copper. Dr. Tidy objected to a standard in which the analysis of any article as a whole was not taken account of.He stated that, on referring to Dr. Letheby’s old note books, he found that he (Dr. Letheby) examined the milk yielded by two cows for 115 consecutive days. The solids not fat in the milk of one cow never fell below 9 per cent., but in the milk from the other cow, on foyr different occasions, the amount of solids not fat was less than 7.5 per cent.He thought, however, there were ninety-nine chances in a hundred that milk which gave such a figure as thia was adulterated, He gave some114 THE ANA&YST. interesting statistics as to the average total solids found in human milk in health and disease, which led him to the opinion that in some cases the children of diseased women appeared to thrive on milk which contained far less total solids than in other cases where the proportion was abnormally high.Mr. Bell stated that at Somerset House they did not subscribe to the limits laid down by the Society of Public Analysts, because having taken great trouble to investigate the subject of milk, they had found considerable variations in its com- position, and that no one constituent forms a, constant quantity in genuine milk.In judging whether a milk had been watered or not they took the whole of the constituents into account, and formed from these an opinion as to the genuineness or otherwise of the sampl6." Mr. Bell then gave some statistics of the examination which they had made of the character of various samples of milk, which are no doubt of interest, but would have been more so had they been given in a rather more intelligible form.The net result appears to be, that in the case of individual cows 4 per cent. yielded less than 11 per cent. of total solids, and 18 per cent. less than 8.6 per oent, of solids not fat ; while iu the case of dairy mixture 20 per cent. showed less than 12 per cent.of total solids, and 12 per cent. contained less than 8.6 per cent. of solids not fat. In the case of individual cows only 6 per cent. yielded less than 2-45 per cent, of fat, and in the case of dairy mixtures only 4 per cent. were found to contain under 3 per cent. of fat. Mr. Bell evidently considered the Society's limit of 2.5 per cent, fat in milk too low. It appears to us a singularly unfortunate thing, that when Mr. Bell was asked to meet the Society of Public Analysts, in order to give them the very information contained in this speech, and to discuss the matter with those who are presumably most capable of dealing with the subject, he should have sheltered himself behid letter from the Inland Revenue Commissioners stating that they did not '( think it expedient ') he should meet the Society, and then that Mr.Bell should have brought these atatistics forward on an occasion when they could scarcely be discussed with equal knowledge or authority. After a few remarks with reference to the question of salt in beer the discusaion was adjourned. In resuming the discussion on April 214 Professor Attfield said he thought a good deal more should be done towards settling the limits or standards. After healing the remarks of Dr.Voelcker and Mr. Bell, he thought they ought to be revised. He could not subscribe to the statements of the Society. Professor Attfield then criticised at some length the '( limits " of the Society, asking whether even salt must be sold free from arsenic. A communication was then read from Mr.Angel1 on the subject of milk, supporting the Society's standard of 9.0 solids not fat. M i . Hehner somewhat severely criticised Dr. Voelcker's and Mr. Bell's figures, and pointed out that it was incredible that Public Analysts all over the country should have made such an erroneous estimate as 9.0 of solids not fat in milk, as waB * We fancy this remark of Mr.Bell's must be misreported, for a copy of a certificate relating to a milk sample is now lying before us signed by Mr. Bell and his coadjutors, and bearing a date in last month,in which certificate no determination of ash is given, and no estimation of the constituents contained in that ash, and this notwithstanding that the milk had been condemned by a Public Analyst, partly beo&use sdt or other preservative material had been added to it.-EDITORS.hbTbLPsT.THE ANALYST.116 implied by M i . Bell’s statements. He also denounced the sp. gr. of fat process as unreliable for butters, and traced the high percentsge of fatty acids sometimes found at Somerset House to imperfect washing. He concluded by protesting against “ secret ” methods of analysis.Dr. Duprd pointed out that in every case in which he had received a milk containing less than 8.6 per cent, solids not fat, he had given a certificate of adulteration ; and in all those cases a prosecution had ensued, and a fine had been inflicted and paid ; a pretty conclusive proof that the vendors did not dare to appeal. He then brought forward some experiments which entirely controverted the remarks of the President as to the effect of cream on the hydrometer.Dr. Alder Wright made a few remarks in reference to the hydrometer to the same effect. Mr, Neison put the hydrometer question in a still more intelligible form, and pointed out that it was simply a measure of the weight of the column of liquid above it. Mr. Bannister referred to certain articles in THE ANALYST, to show that the term standards was sometimes used instead of limits even in this journal ; but his quotation seems to us to apply really to Mr.Wanklyn’s C‘ standard,” not to the Society’s ((limit.” He then referred to two well-known old cases in which analysts had unquestionably made mistakes, both of which cases were immediately and promptly dealt with by the Society of Public Analysts.Of this latter fact Mr. Bannister made no mention. After a few remarks from Dr. Dupr6, expressing surprise at some remarks of Mr. Bannister’s, Mr. Helm did little more than reiterate Mr. Bell and Mr. Bannister’s statements in reference to milk. He complained however of the low fines when samples were proved to be adulterated, and introduced a personal element into the matter, by pointing out that his own milkman had just been fined.After Mr. Bell had again defended the sp. gr. test for butter, Dr. Alder Wright said he thought the amount of added water should be calculated from the limit used in the case of milk, and not from the average results of general samples ; but, from his remmks, it would appear that he did not understad that this was the course almost invariably taken by Public Analysts.He then referred again to the hydrometer, and clearly showed that the statements first made about it were incorrect. The President, in his concluding remarks, appeared to think that the troublous times of the Public Analysts were coming to a conclusion, and that chemists were rapidly converging to fairly unanimous opinions as to the processes and limits or standards. He thought there should be a difference between the fine inflicted upon the man who intentionally adds water to his milk rtnd the man who sells milk from a poor cow ; and therefore he thought there should be two standards, one of average quality and one of minimum, and that any milk falling between the two should be regarded not as adulterated but as not of the qudity demanded. The President then made some rather strong remarks in reference to low fees paid for analytical determinations, suoh for instance as 2s. Gd. or 5s., and the discussion mas concluded with a vote of thanks to Dr. Voelcker, and its acknowledgment by him.