INSTITUTE OF CHEMISTRY OF GREAT BRITAIN AND IRELAND, REPORT OF i4 CONFERENCE ON THE ADULTERATION OF FOOD, Held Thursduy, liebruury 27th, 1879. YJunbalt : PRINTED BY A. P. BLUNDELL -& Co., 26, GARLICK HILL, E.C. 1879. INSTITUTE OF CHEMISTRY. CONFERENCE ON THE ADULTERATION OF FOOD, DR.VOELCKERsaid-In opening the discussion on the subject of Adulteration of Food, I need not take up the time of the nieeting by making any preliminary reinarks on the importance of the subject to the general pnblic, the serious responsibilities with which public food analysts are charged in drawing up reports on the genuineness of articles of consumption, and tlie necessity of the adoption of trustworthy and accurate methods of analysis in the examination of articles of food and drink.We are all agreed in this that Nilk, Butter, Bread, Beer, Spirits, and all articles of food or drink should be supplied to the consunier by the trading community in a perfectly wholeso~~e and genuine condition, and under names correctly describing the character of the several articles of con-sumption. There can be no doubt that the Food Adulteration Act has had a beneficial influence in checking the nefarious dealings of unscrupulous tradesmen, and providing the consumer more readily with pure articles of food and drink tliari before the Act came into operation. It is coniparatively easy to define wliat legally constitutes Adulteration, but it is much more difficnlt for H food analyst to 28 apply the legal definition in practice without running the risk of either of letting the guilty escape just punishment, or to inflict undeserved in jury on honest tradespeople.It is easy enough to ascertain whether milk has been adulterated with a considerable quantity, say 20 per cent., of water, or whether skimmed milk has been sold as fresh, or m-hether or not coffee is adulterated with chicory, or whether bread contains much alum. In cases of that kind the chemical or microscopical examination of the articles in question decides with certaint,y whether they are genuine or adulterated ; but when we have to deal with articles of food which naturally vary in composition, the difficulties in deciding whether such articles have been tampered with are all the greater the more they naturally vary in composition. Take as an example the case of milk.Genuine milk we understand to be the well known secretion in the condition in which it leaves the udder of healthy cows, nothing haring been added to the milk, nor any cream having been abstracted from it. The question, what is the composition of such genuine milk? admits of a variety of answers, for I need hardly say that it is now admitted by all persons who possess some knowledge of dairy matters that the composition of equally genuine samples of milk varies greatly, and that there is no such thing in existence at3 normal milk. As long ago as in 1863 I directed attention to the great influence which the nature of the food upon which cows are fed has on the composition of the milk they furnish, and pointed out in what way the quality of the milk is affected by the breed of cows and the size of the animal, the season of the year, the distance from the time of calving, and a few other conditions, which all more or less affect the qnality of the niilk.Thus, a herd of cows fed upon an insufficient amount of grass froin a poor pasture, and milked in my presence, produced niilk which, on analysis, in round numbers yielded fully 90 per cent. of water, and only 10 per cent. of total solids, including not quite 2 per cent. of fat ; whilst the same herd in the following months, mlien liberally fed upon palm-nut kernel meal, a food rich in fat, 29 in addition to sliced mangolds and good hay, produced milk con- taining from 32 to 4 per cent. of fat, $I&to 10 per cent.of solids not fat, and only 86 to 87 per cent. of water. Again, in the milk of another herd of cows in August, I found 87.40 per cent. of water, 3-43per cent. of fat, 9-17 solids not fat 3 and in the milk of the same herdof COKS analysed in November, I found 85-21 per cent. of water, 4.95 per cent. of fat, and 9-84 per cent. solids not fat. Here, then, we have in equally genuine milk the total solids varying from 10 to 15 per cent., and the fat varying from 2 to 5 per cent. in round numbers. In passing I may observe that in ten or twelve days from the time of calving, after the milk has assunied its ordinary condition, the flow of milk is plentiful and continues so for a couple of months ;it then diminishes in quantity, but becomes richer in quality, and more especially in cream.Thus in the spring and early summer months, cows produce abundance of milk, but of a more watery character than towards the approach of autumn, when the supply diminishes, but becomes richer in cream. Again, small breeds, such as Alderney and Jersey cows, generally speaking, produce less, but richer, milk, than large races, such as the Yorkshire cow, a cross-bred short-horn, or Dutch cows, or other large-sized animals. In view of these natural variations in unquestionably genuine milk, what is the analyst to do in reporting upon a sample of milk suspected to have been watered? Is it possible, I would ask, for a chemist to declare positively, on the strength of his analysis-as has been done in not a few instances by public analysts-that samples of milk were adulterated with 10, 8, or even 5 per cent.of added water. I have seen a report of a chemist who positively states that 12.8 per cent of skimmed milk had beenadded to milk, and on the strength of such an opinion, the magisbrate inflicted a fine upon the unfortunate milkman. In carrying out legislative measures of the nature of the Food Adulteration Act, you will agree with nie that great care should be taken to prevent its becoining a dead letter, on the one hand, 30 and on the other, to guard against undeserved injury being done to honest traders.Now in the case of milk: what has been done in that direction? This qnestion may be briefly answered as follows : Public analysts at first adopted H standard of quality, based on the supposition t!iat the coniposition of genuine milk does not vary to any great extent, and that, more especially the percentage of solids, not fat,, practically is constant in all genuine milks. In practice, the adopted standard of quality was found too high, and was lowered subsequently. Applying the preseiit standard rigidly, most public analysts calculate to a nicety the amount of water added to, or cream abstracted from, milk, by a simple rule vith which most of those present on this occasion are perfectly familiar. The author of this plan of estimating the exact percentage of added water in milk, says, '' Milk exhibits great constancy of composition; the effect of variations in the diet of the cow, showing itself in the amount of the secretion, rather than in its quality; and again, as wiIl be readily comprehended, this constancy of com-position is a cardiual fact in milk analysis.When I first opposed thia theory of the constancy of com-position of milk, I rnet with the ridicule of not a few public analysts, some of whom where so ungenerous, not to say unjust, as to call in question the correctness of my milk analyses,whilst a few, no doubt very young and inexperienced analysts, were bold enough to maintain that great improvements had been introduced of late years in the analysis of milk, and that no good or accurate method of analysing milk was known at the time when I published a paper on milk in the Journal of the Royal Agricultural Society in 1863.By degrees my opponents-at least, the best informed of them -altered their views on the milk question, and more and more come round to my own. The analysis of milk is so simple an operation that I need not say anything on this head ; surely any properly trained analyst may be charitably supposed to be able to determine the exact percentage of water, fat, and ash in milk, and 31 I fail to see that the plan I invariably follow in weighing the fat and not determining it by difference, is less accurate on this account, or because I generally work upon 5-10 times the quantities of milk which now-a-days some chemists employ in rapid and cheap analyses.In passing I may observe that it is it disgrace to our profession that analysts can be found who make milk analyses at the munificent rate of two shillings and sixpence to five shillings a-piece. However, to return to the discussion respecting the propriety of adopting the present standard used by most public analysts, or any other standard, I would observe at once that I object in foto to all standards whereby to judge of the exact amount of water added to milk, on the ground that such standards are based on wrong principles, and are often mischievous in practice. The effect of the adoption of the present somewhat lorn standard, in my judgment, does harm, because for the greater part of the year it enables milkmen to take off a certain quantity of cream from milk, and to dilute it up to the requirements of the standard quality, without laying themselves open to fines.On the other hand, if a high standard is chosen, injustice may be done at certain times in the year, when the quality of the niilk naturally is much poorer than at others. There is no denying the fact that there is considerable difficulty in meeting this case. It does not appear feasible nor just to legislate to the effect that all milk must be sold of a guaranteed composition, or not below a certain standard quality, €or such a rule would at once give rise to abuses, and promote, rather than restrict, the manipulation of milk.But, it may be asked, can nothing be done effectually to stop the adulteration of milk :Z My answer to this question is, certainly, much may be done in this direction, if only chemists will exercise their judgment properly, be taught by experience, and deport themselves as sensible men, and show themselves to be something more than mere analysing machines. As long as the world is going to last, I fear there will alnTays be men who mill go, as far as they can safely do so, in a wrong direction, without actually breaking the laws of the ~IHE~XJ'. These are the clever, and for this reason, far more mischievous rogues of Society than the doimright vagabonds who rob their neighbours in broad daylight, and, unfortunately, aubtle roguery cannot be cured by legislative measures, and it is only against the more open or grosser vices that human laws can be devised and enforced effectuiilly.In the case of milk prosecutions, it appears to me public analysts should exercise more discretion, and not condemn a milk if, according to the present standard method, it shows 5, or even 10, per cent. of added water at a time of the year when milk naturally is more watery than ab other periods. Would not the same ends be reached if public officers mere appointed to inspect milk shops, and take from time to time samples for analysis? If a sample of milk sold were reported to be watery and poor in cream in comparison with tha$ milk sold by another dealer at the eame time, would the publication of the report not quite as much promote the sale of good milk as a vexatious prosecution ? I do not think there is any difficulty in determining by analysis9 or by even a much more simple means, whether milk is watered to the extent of 20 per cent., or if skimmed milk, instead of fresh milk, has been sold.This leads me to refer briefly to the much despised in- strument for testing roughly the quality of milk,-I mean the gravimeter, and with your permission I would read the following passages from my paper on Milk, which you will find in Vol. XXIV., part iv., of the Journal of the Royal Agri-cultural Society :-''A good many experiments have led me to the conclusion that within certain limits the specific gravity is a trustworthy indicator of quality.It is true that the cream globules are lighter than milk, and thus milk containing much cream bas a lower specific gravity than skim milk; but surely no instrument is required to tell us whether milk is extra rich, or, like skim-milk, poor in cream. The lactometer mas never intended to indicate the 33 relative richness of extra good samples of milk, but it was designed to be a simple instrument which shonld unmistakably point out whether samples of a fair or doubtful appearance had been watered, or were of a naturally defective composition ;and this purpose it astisfactorily fulfils. ''Some of the objections to the use of hydrometers for testing milk, are based on the mistaken opinion that cream is lighter than water. This is not the case; it is lighter than milk, but denser than water, in the proportion of 1012, or even 1019 to 1000.The addition of cream, therefore, cannot depress the specific gravity of the milk in the same degree as the addition of water. A low specific gravity, therefore, always indicates it large quantity of water ;at all events, I find milk rich in butter, of a gravity that is a good deal higher than milk adulterated with even little water. The results of a few experiments may here be cited, showing the quantity of cream which is thrown on the surface by pure milk of known composition, and milk purposely adulterated with fixed quantities of water, and also the specific gravity of milk adulterated with variable portions of water.''The milk used in the first set of experiments had the following composition:-Water ..........86.00 Pure fat (butter) ........ 3.71 *Casein and albumen ...... 3.37 Milk-sugar .......... 5.31 Mineral matters ........ -81 100*00 *Containing nitrogen ...... a54 Percentage of solid matter ....13.20 '(This milk had a sp. gr. of 1.0320 at 62"F. After standing for 15 hours it threw up 11.5 per cent. of cream by volume, having a sp. gr. of 1,0183at 62" F. 'c Portions of the milk were mixed with 10,20, 30,40,and 50 per cent, of water respectively, and the specific gravity of eack eample 34 thus diIuted with water was compared with that of pure milk, when the following results were obtained :-Percentage%;,it;.of Cream in bulk. Pure milk at 62O F. ........ 1.0320 ..ll+ ,, and 10 per cent. of water at 62' F. .. 1.0315 .. 10 19 ,320 .. 1,0305 .. 919 11 9,30 ,l .. 1.0290 .. 8 11 40 99 93 .. 1.0190 .. 6 60 9, .. 1.0160 ... 53, 1, "After removal of the cream from each sample, the specific gravity of the skim-milk at 62" F. was determined, and found to be as follows :-Pure skim milk ............ 1.0350 .. and 10 per cent. of water ...... 1.0320 20 and 30 per cent. of water (spoiled by accident). 99 11 40 per cent. of water ...... 1.0210 50 9, ...... 1.018019 ((In the preceding experiments the specific gravity of the milk was determined by means of an hydrometer; but as results obtained in this way are not considered so accurate as determi-nations made by direct weighings on a delicate balsnce, and, moreover, as the second of the series accidentally failed, a second set of experiments was made. *'The milk was analysed, and had the folloming composition :-Water ..........88.10 Pure fatty matters (butter) ....2.61 *Casein and albumen ...... 3.12 Milk-sugar .......... 6.46 Mineral matters (ash) ...... -71 100~00 *Containing nitrogen .... *50 Percentage of solid matter ....11.90 €6 Its sp. gr. at 62*, ascertained by hydrometer, was 1-0320;and by direct weighing 1.03141. After standing 24 hours it gave 12 35 per cent. of cream by volume; having been shaken, and then left to stand for 24 lloiirs, it pve 8 per cent.of cream by volume : Percentage ot Cream by bulk. This milk and 10 per cent. of water, after 24 hours’ standing at 62O, gave 10,; 93I, 20 1, ’7 ?I 10 30 619 ’1 ?I $7 I’ 97 40 ’I 9’ ?? 31 5 ,> 60 ,? 4;’1 Y’ ?I “The relative proportions of cream in these samples do not agree with theamount of water that has been pnrposely added to each. I account for these variations by the fact that in mixing the milk and water together, the cream globules hare been more or less broken, accordiiig to the degree of agitation to which the milk was exposed, in consequence of which the cream in the different samples had a variable composition. ‘‘On comparing the milk of the second set of experiments with that of the first set,it will be seen that the latter, notwithstanding it contained more pure fatty matter, threw up a little less cream in bulk than the former.“The subjoined table gives the specific gravity of the different samples of milk used in the second set of experiments, before and after skimming. All determinations were made at 62” F. ~~ -Specific Gravity at 629 F. Specific at 62P F.before skimming. after skimming. Pure milk .. .. .. .. .. 1.0320 1-03141 1-0337 ,, + 10 per cent, of water 1.0285 1.0295 1.0308 I? 3-20 ,, ,* .. 1.0250 1.0257 1.0265 4-30 99 I, + 1.0235 1.0233 1.0248$3 1.0200 1.0190 1.0208I) -I-40 1) 99 * 1.0170 1.0163 1.017593 + 50 I9 99 ‘‘This second serieg of experiments was made with great care, and the numbers obtained are probably more trustworthy than those of the first series. ‘‘It will be seen that the hydrometer indications agree very nearly with the specific gravity determinations by direct weighings.It follows, further, from the preceding experiments :-I‘ 1. That good new milk has a specific gravity of about 1.030. “2. That skim-milk is a little more dense than new milk, its specific gravity being about 1’034, “ 3. That milk which has a specific gravity of 1.025, or less, is either mixed with water, or naturally very poor. ‘‘4. That when milk is deprived of about 10 per cent. of cream by bulk, and the original volume is made up by 10 per cent. of waster, the specific gravity of such skimmed and watered milk is about the same as that of good new milk.‘45. That when unskimmed milk is mixed with only 20 per cent. of water, the admixture of water is indicated at once by the hydrometer, which gives for such milk a specific gravity of about 1.025. “ 6. That for these reasons the hydrometer, or lactometer,’ which gives the specific gravity of milk, is well adapted for detecting the admixture of water in milk, or to show an unusually poor condition of undiluted milk. No. 4 do not by any means prove that the hydrometer gives unreliable results ;for although it is quite true that by substituting 10 per cent. of water for 10 per cent. of cream, the original gravity of the new milk is preserved, it may be observed that milk skimmed to that extent cannot be mixed with Kater without becoming so blue and transparent that adulteration cannot be practised.At all events if it should occur, no instrument whatever is required to detect it.” Passing from milk to cream, I would ask the question, what is the composition of genuine cream ? The following are a few analyses, which show how even genuine cream varies in composition :-conclusion, it map be stated that the facts mentioned under In 4‘ 37 1 1I. 11. III. IV. Water .. .. .. ., .. 74.46 64.80 56.50 61-67 Butter (pm fatty matters) 18.18 25.40 31.57 33-43 *CaseinMilk-sugar . . . . ,.., . . i::: { 7-611 { 8.44) !:!: Mineral matters (aah) .. 0.59 2.19 3.49 0.72 100~00 100*00 100~00 100~00 *Containing nitrogen.. 1 *43 1 .. .. 1 .. .. -42 ~ “Cream is lighter than milk, but slightly denser than pure water ; consequently it sinks in distilled water.No. 1 was skimmed off after standing for 15 hours, and was found to hare a specific gravity of 1.094 at 62” F. The specific gravity of two other samples of cream which stood 48 hours was 1-0127 at 620 F., and 1-0129 at 62” F. Rich cream, I find, has a lower specific gravity than thin cream mixed with a good deal of milk, such ILIJ the sample analysed under No. 1. ‘‘No. 2 may be taken as representing the composition of cream of average richnem. It then contains about one-fourth its weight of pure butter. 66 These differences in the composition of cream fully explain the rariable quantities of butter which are produced by a given bulk of cream.” I have spoken somewhat fully on the adulteration of milk, because it is a subject on which I have had, perhaps, more extensive and varied experience than most people, and because it occupies so prominent a place in the occupation of public analysts.Intimately connected with milk and cream is butter. A good deal of useful and careful work on butter analysis has lately been done by Mr. Bell, Mr. Hehner, Dr. Duprk, and others, and as some of these gentlemen are present to-night, they will, perhaps, give us the benefit of their experience; I therefore pass on to throw out as a hint for discussion, the question of how much alumina may be allowed to be present in bread, as due to earthy matters which may have been in the flour used in baking 38 the bread, and the best methods of detecting the presence of alum in bread.I hardly think we need occupy our time in talking about adulterated tea, coffee, cocoa, and arrowroot, and I would only make a single remark about the examination of vinegar supposed to have been adulterated with sulphuric acid, or, rather, to say a word of caution to food analysts, namely, to be careful to distinguish between free and combined sulphuric acid. A few years ago, Messrs. Hill & Evans, the eminent vinegar makers, of Worcester, requested me to analyse their vinegar, which had been declared by several food analysts to have been largely adulterated with sulphuric acid, but in the manufacture of which not even 1 part of sulphuric acid in 1000 was used, the very hard water, containing much gypsum, used in the Worcester Vinegar Works, having been found to answer all the purposes of adding the small quantity of sulphuric acid allowed by law.In the next place, allow me to suggest to you for discussion the question of how far the colouring of articles of food is allowable, or whether it has to be regarded as coming within the provisions of the Adulteration Act. I would ask the question should it be permitted to colour milk with annotta or carrots, so as to give it the appearance of richness. Snd again, if milk is not to be coloured, should it be lawful to colour butter or cheese ? In my judgment, all harmless colourings, although having a mark of deception, might be passed orer without notice.The use of metallic, or other poisonous matters, in colouring articles of food or confectionery, should, in my opinion, be regarded as a punishable offence, and on no account be permitted, even in preparations in which, as in the case of peas coloured green by copper, the amount of poisonous matter may not be so large as to effect in any way the health of those who partake of the coloured substances. There is another matter in connection with the adulteration of food, to which I would briefly direct your attcntion and on which invite discussion ; I refer to substances ~~'hich are used ~.itli the 39 avowed intention of preserving perishable articles of consumption, such as milk, meat, butter, &c.Of course, I do not refer to the use of common salt or sugar, or spices, or any equally harmless matters, but have in view compounds which have a more or less powerful medicinal effect when taken internally. At the present time, as you are aware, salicylic acid is frequently recommended as a preservative of food. Thus, Dr. Van Heyden, of Dresden, recommends to add one-third of a tea-spoonful of the solid acid to aquart of milk. I do not know what you think of bringing-up babies, if you have any, on milk containing per quart + of a tea-spoonful of solid salicylic acid; for my own part I should be sorry to drink myself such doctored milk, or to give it to my children. In conclusion, I would invite discussion on the subject of the adulteration of spirits? What, it may be asked, is brandy? Should burnt sugar be allowed to be added to brandy? Why should a man be fined for selling gin, as gin, if it be diluted with much water? Are not all spirits mixtures of alcohol and water? Why should spirit of a certain strength only be called gin or whiskey, and not, if it contaius a larger proportion of water ? I am not a teetotaller myself, but I think it would be a very good thing indeed for the people frequenting public-houses, if they got very little alcohol and much water in the spirits they drink there.If a man is to be fined if he sells gin that contains much water, why should a man not be punished if he sells very thin beer ? I would further throw out the suggestion to discuss the subject of adulteration of wines and beer.It appears to me unjust and absurd to fine a man in whose beer 20 or 30, or even 80, grains of common salt are found per gallon. How much salt, I would ask, does every man eat with his breakfast or dinner ? If he drinks a pint or a quart of salted beer, how much salt does that add to the salt in the meal he takes? In a scientific and chemical point of view, some of the sug- 40 gestions which I have thrown out for discussion may be considered to be trivial and not worth talking about. However, food analysts, be it remembered, have a good deal to do with an un-scientific public, and it ie unquestionably a matter of some importance for food analysts to entertain reasonable and sound views on chemical points relating to foods and drinks, for the attitude which food analysts assume will necessarily -influence public opinion, and either strengthen or weaken the regard in which our profession is held by the public at large, and, taking this view of the matter, I do not think our discussion to-night will be regarded as trivial or useless.THE PRESIDENTsaid: We have before us to-night a very wide subject, and one which is full of difficulty, not only for the vendor and legislator, but also for the chemist. I am sure you will agree with me that we are very fortunate in having the subject introduced to us by Dr. Voelcker, who is so thoroughly acquainted with at least one branch of it, namely, the chemistry of milk. As for myself, I am here as a learner, since I have had but little experience in connection with adulteration.I have, however, listened to Dr. Voelcker’s remarks concerning milk with considerable interest, for at one time of my life I was in the habit of spending a few weeks occasionally at a dairy ; and I remember that it was always in the power of the farmer to make a con-siderable difference in the quality of the milk, according as he mixed the whole of the produce together, or divided it into two portions (a very common custom), reserving the ‘‘strippings,” or last flow of each cow, for butter, selling only the remainder, or poorer portion. Although I have ZI weakness for standards, and have sometimes been blamed for advocating them, I must admit that there is some force in Dr.Voelcker’s argument against their me, so far as milk is concerned. At the same time, a rea-sonable amount of pressure might be put upon the seller. If it farmer sells milk from which the best part is excluded, although the milk is actually sold as it comes from the cow, he ought, in my opinion, to be fined, because it is in his power to improve the quality of his milk so as to bring it up to a reasonable standard. 41 Without in any way wishing to narrow the discussion, I may remark that the subject will probably divide itself into two main lines, namely : adulteration, and the means, both qualitative and quantitative, for its detection. Definitions of adulteration ought to protect the public so far as it is possible ; but hhey ought not to throw too much onus on the ignorant trader, for me cannot expect retail dealers to be either chemists or physicists. There is one point which Dr.Toelcker mentioned in his introduction relating to the specific gravity of' milk, and the objections to the use of the lactometer, on account of the comparative lightness of the fat, or cream globules, about which I should like to hare a word of explanation. Was it the ordinary lactometer to which his remarks applied ? DR. VOELCKER:Yes. THEPRESIDENT: Then Dr. Voelcker is perfectly right in the conclusion he draws, because the quantity of fat present would exercise no influence on the indications of the lactometer. Imagine for a rnorneiit you are taking the specific gravity of a sample of water, full of moving organisms; these organisms might be heavier or lighter than water, but iu neither case would they exercise any influence on the iiiclications of the hydrometer.The globules of fat are, I believe, freely suspended in milk, each one being surrounded by the aqueous liquid. They would, therefore, have no effect on the lactometer. DR. DUPR~ :I must say a few words in favour of public analysts, for I have no hesitation in stating that the Society of Public Analysts is as well able to deal with the subject of adulteration as the Institute of Chemistry of Great Britain and Ireland. Even clever chemists may make mistakes, as Dr. Voelcker himself did when he said the Society of Public Analysts had laid down standards.On the contrary, they alvmys protested against them. It is true we have laid down certain limits, but this is a very different thing. We consider everythiiig which falls below a certain limit as adulterated, but this limit, below which everything is rejected, is a very low one. As regards the definition of adulteration, it must be remembered that the Act of Parliainent is not an Adulteration Act, 42 but a Sale of Food and Driigs Act; the word adulteration is entirely excluded from the Act. There is no such thing as an adulterated article, but only an article which is not of the nature, quality, and substance demanded. If, hovever, a definition of adulteration is wanted, there cannot be better ones than those laid down by the Society of Public Analysts, who may be bad chemists, but who certainly have some common sense.These definitions were reprinted in several German papers, but I have not seen them in any English ones. They are as follows : DEFINITION OF AN ADULTERATED ARTICLE. An tcrticle shall be deemed to be adulterated : (A) In the case of food or drink-1. If it coutain any ingredient which may render such article injurious to the health of a consumer. 2. If it contain any substance that sensibly increases its weight, bulk, or strength, or gives it a fictitious value, unless the amount of such substance present be due to circumstances necessarily appertaining to its collection or manufacture, or be necessary for its preservation, or unless the presence thereof be acknowledged at the time of sale.3. If any important constituent has been wholly or in part abstracted, unless acknowledgment of such abstraction or omission be made at the time of sale. 4. If it be an imitation of, or be sold under the name of, another article. (B) In the case of drug,+--1. If,when retailed for medicinal purposes under a name recognised in the British Pharrnacopceia, it be not equal in strength and purity to the standard laid down in that work. 2. If, when sold under a name not recognised in the British Phar- mscopceia, it differ materially from the standard laid down in approved works on Materia Medica, or the professed standard under which it is sold. To go back to the question of milk, I repeat that there is no such thing as adulteration, but as an article which is not of the nature, quality, and substance demanded.I mention this to bring forward the instance of the starving COTS. Now, if I vant to have milk, I want it as supplied by ahealthy con-, properly fed. If I have it from a starving cow, I might as well have it from one 43 that is diseased-the milk is not of the natnre, &c., &c., demanded, and fairly comes under the operetion of the Act. I think Dr. Voelcker’s analyses have done a good deal of harm by lowering the hit unnecessarily ; it enabled farmcrs and milk dealers to bring forward instaiices where cows have supplied milk containing a less amount than 9 per cent. of solids not fat, Even in the case of starring cows ttie amount of solids was not much less than 9 per cent.He also stated that no niilk which contained 3+ per cent. of fat could be adulterated. I must entirely differ from that. Only very recently I had a sample which gare 60 per cent. of cream, or 15 per cent. of fat, and yet I should not have had the slightest hesitation in saying that this milk was adultera,ted, if the solids not tht Elad falIeii below my limit of 9 per cent., after taking the excessive proportion of fat into consideration. You must remember that articles of food for analysis are bought by inspectors-the public take very little interest in the matter. have been eugaged as a public analyst five or six years, and only remember one occasion where the article was not brought by the inspector. Every dealer knows the inspector, and, of course, the latter is served with a good article, and, in the case I have mentioned, the sample had evidently been carefully taken from the top of a can mliich had stood some time, nevertheless, the milk itself might have been adulterated.As to alumina in bread, I do not think that any limit can be laid down, bccause the amount present differs very much, according to the purity of the materials. There is at least one compound of alumina, naniely the soil in which the wheat has been grown, and more or less of which adheres to the grain, which, unless present in excessive proportion, cannot be looked up011 as an adulteration. All re can therefore, contend for, is, that the alumina fouud should not exceed a certain proportion of the silica present.What that proportion should be will have to be decided by a large number of analyses, but when once fixed it may furnish a means, the only means as far as I can see at present, for estimating the amount of alum contained in a given sample of bread. Slum added to flour can be estimated with ease and exactness by the method described by myself a little while ago, and printed in The Analyst, for January, 1879. With reference to butter, I must differ from Dr. Voelcker in regard to the value he seems to attach to the specific gravity of pure butter fat, and any public analyst who relied upon this method would be liable to class pure mutton fat as pure butter, as the specific gravity of some samples of mutton fat is as high as that of butter fat.A great difference of opinion has been expressed as to the amonnt of fatty acids insoluble in water contained in pure butter fat, but I am decidedly of opinion that most, if not all, of the high results given, are simply due to errors of analysis, that is, to insufficknt washing of the insoluble acids. No analysis of butter fat giving a high percentage of insoluble acids was worth anything unless the soInble fatty acids are given at the same time, so that both may be calculated into fat. Whenever the fatty acids, plus their glycerine residues, come to much above 98 per cent. of the butter fat taken, the andysis may be looked upon as Forthless (taking the molecular weight of the insoluble acids at 278*,and that of the soluble at 88.).Towards the end of the washing, for, say 1 per cent., of acid we wash out of the so-called insolnble acids, we add only per cent., or even less, to the soluble acids, if TTe assume, as is usually done, that the soluble acids consist of butyric acid only. There are one or two considerations upon which I should like to remark, not, perhaps, strictly chemical, but which are as important as any chemical question that can be raised. First of all, the ridiculousIy low fines inflicted by some magistrates. There are such fines as five shillings or two-shillings and sixpence for milk adulterated with only ten per cent. of Tvater. 01zIy ten per cent.of Tater in t.he milk consumed in London means 32150,000 a-year paid for water ; a five shilling fine means the sale of 12 quarts of water, and there are few dealers who cannot get through 12 qumtsof water between two visits of the inspector, who cannot go too often,or it Todd be called persecution. There are some milk dealers to whom an adulteration of 10 per cent. means S.1000 a-year gained by the sale of water. In conclusion, Dr. Dup4 said, that with respect to a definition of what redly constituted adulteration, he was afraid there would be a great difference of opinion, as what one would hold mas adulteration, another would say was not, and he instanced the case of drugs, which by long keeping would be liable to changes.In Germany an inspection of all chemists’ shops took place every year, and every chemist was bound to keep his drugs up to the prescribed standard. This was a question which he thought the Institute of Chemistry might well take tip. DR. STEVENSOX:I must re-echo a good deal of what has fallen from Dr. Dupr6 with regard to public analysts. As a public analyst I have had to listen to some rather strong language from Dr. Voelcker, who does not seem to have one word to say in their favour. Of course, there are public analysts and public analysts ; but as a body, I believe they are as trustworthy as the members of any other profession. I was also sorry to find the paper referred to so few subjects and introduced so little new matter. THE PRESIDENT: It would be unfair to Ur.Voelcker if we regard his paper as an original communication. It is not so intended, but merely to furnish the basis for the discussion. DR. STEVENSON:I was coining to that, because chemists have been condemned by Dr. Voelcker on the strength of old analyses made by methods now scarcely ever adopted by analysts. Milk analysis has been much improred, and with more modern methods we have more accurate results. It would have been well if the old had been tested by comparison with the new methods. As to standards, I differ from Dr. Voelcker and agree Fith Dr. Dupr6, when he said it would be rery unwise if analysts were not to have standards below which articles should not fall. With regard to milk, I may say that I am well acquainted with all agricultural operations, and made many analyses of milk direct from farms, following up the subject scientifically.I have had the oppor- tunity with milk of a great number of cows, and have had access to a large number of dairies, taking individual cases as well as large herds. The milk of fairly fed cows I consider does not present that wide difference which we have heard this eTening. A cow, of course, might he found to have a low quality of milk from an exceptional cause, but not so frequetitly as Dr. Voelcker stated. As to alum in bread, very little has been added to our knowledge from what Dr. Voelcker has said, I quite agree with Dr. Dupr6 in not relying on the alumina, alone, for there are few samples of bread tested which do not show a certain quantity of alumina.It is as well, therefore, to apply the logwood test, and to determine the amount of silica. I should like to hear the opinion of the meeting on drugs, because the Local Government Board have drawn attention to the fact of so few drugs being analysed by the public analysts. Apparently the question has not been settled as to whether when a drug is sold to their inspector under the name of a preparation of the British Pharmacopceia, the vendor is bound to sell it of a quality laid down in the Pharmacopceia. Suppose iron and quinine asked for-THE PRESIDENT:The question of drugs would make a very interesting discussion, but it would be better to have a separate evening for this subject.DR. STEVEKSON:It is the Sale of Food and Drugs Act I thought we were discussing. I understood we were to discuss drugs as well as food. It is a point which is just now mnch exercising the minds of public analysts. THE PRESIDENTobserved that he would take the sense of the meeting as to whether drugs should be discussed, and the question having been decided in the negative, DR. STEVENSONsaid he quite coincided in the decision. Passing on to speak of spirits, he said : I do not think, because all spirits are, as has been remarked, more or less mixtures of aleohol and water, it implied that the vendor should be allowed to sell any mixture of water and spirits as genuine. We know from the evidence of the Customs and Excise that most spirits, except perhaps rum, when imporked or manufactured are of certain definite strengths. It is the custom to dilute these in various ways, and although no standard is laid down by law, yet there is one laid dom-n by custom.We cannot fall into much error with 47 brandy, gin and whiskey, but rum is different. As to whether brandy distilled from wine should be distinguished from brandy made from corn-spirit and flavoured with an essential oil, and the latter spirit be termed adulteratsd, there is a difference of opinion. I think, however, that most public analysts in this respect have decided in favour of the vendor who supplies the last named compounds. I hope Dr. T'oelcker, because I said his matter was old, will not think I undervalue what he has said, but I regret as to milk that we have not had more recent evidence from him.DR. VOELCKER:1 make every year a great many analyses of milk, and my recent experience but confirms what I hare already said. I have not had to retract a single word, for nothing new has come out. DR. REDWOODsaid that not only had there been suficient matter introduced for discussion, but that there was more than they could cornpletcly discuss in one evening. He had been glad to observe that Dr. Voelcker had not attempted to define the meaning of adulteration, for he felt satisficd they might discuss it, not only for hours, but for days, without coming to any satis- factory conclusion. It would be much better to confine themselves to the question of what the articles of food vere that n-ere most subject to adulteration in the commonly accepted sense of that term, and what the kiqds of adulteration were that were most objectionable, as affecting the health of the consumer or the pocket of the purchaser.Some of the subjects introduced had been pretty fully dealt with, but others, and especially two or three of those last touched upon by Dr. Voelcker, had been but sliglitly referred to. It was with reference to these he proposed making Borne remarks. He agreed with Dr. Steyenson respecting the adulteration of spirits. There were certain limits in regard to strength within which potable spirits should be kept in order to justify the application to them of their popular names.This had been taken as the basis of a decision by the Judges in one of the superior Courts in an appeal case. The question &-as asked by them, what was the usual strength of the spirit sold under that particular name by thebetter class of dealers in the locality in 48 which the sample in question was obtained ;-and that was taken to be what the public had a right to expect when they asked for the article under that name. Gin, for instance, was supplied bg the rectifier to publicans at 17" or 22" under proof, but this was generally reduced to 30" under prbof by the publican before he Bold it. The public, in fact, rarely obtained it by retail either stronger or weaker than 30" under proof. There were, however, a few unscrupulous dealers who lowered it doKn to 40°,or more, under proof, and the question was, had the public a right to complain in such cases.Dr. Voelcker said, and some might be disposed to agree with him, that the more the spirit vas diluted, the better for the health of the public, but he could not agree in that opinion unless all spirit sold under the same name were equally reduced in strength, otherwise the pockets as well as the health of the public would suffer. While the strength varied between 22" and 40" or 50" under proof, there was more danger to health than there would be if the strength were equalised. He thought it was not only necessary to regulate the strength and composition of spirits, such as gin, but also of beers, and if it were possible- but it hardly appeared to be so-of wines.He had devoted a good deal of time and attention to this subject, and had been very anxious that the public should be enabled to get from public houses the genuine beers of the grcat brewers, such as Combe & Go., Meux & Co., Reid & Co., whose names were put up by the publicans to induce the public to belieye that they were selling such beers. He had obtained the co-operation of most of the great London brewers to effect what they all admitted was a desirable object, but unfortunately, although he had commenced successfully, the object had been defeated by the adoption of a practice which became common among the publicans, of putting up a notice that all their alcoholic liquids were diluted, and the magistrates ruled that this exonerated them.One other subject he wished to allude to, namely, the colouring of articles of food. On this point again he could not agree with Dr. Voelcker. He thought if the artificial colouring of such articles aa butter, cheese, pickles and sauces, mere an offence, it was at least a rerj venial 49 one, provided that nothing injurious was employed for the purpose. Take, for instance, the case of butter ; tliat which was imported in bulk was collected- in small quantities from different makers, and was subject to variations of colour which would give the bulk an unsightly appearance, but this was prevented by the addition of a small quaniity of annatto, which gave a uniformly agreeable and natural appearance to the whole.Mow he con-sidered that if by such simple means food could be made to appeal. to, and to satisfy the requirements of, other senses as well as the palate, it would be rendered more wholesome and nutritious than it would be if it offended any one of these. And, therefore, he justified such harmless additions as he had alluded to. Of course, the colouring of pickles with copper was a very different thing, and that he decidedly condemned. DR. TIDY:I do not know how to suggest anything in the place of standards in some form or snother, although I confess they appear to me to be objectionable. The only question is, who is to settle the standard ? Shall every man be a lam unto himself, or shall a society fix a standard, to which, of course, they can bind no one. At any rate, I object to a standard in which the analysis of any article as a whob is not taken count of.For this reason a standard of milk founded on the solids not fat, is, to my mind, unscientific. I do not profess for the past few Tears to have had the experience that has fallen to many in food analysis, but for Some years preceding these adulteration days, I expect, as an assistant to Dr. Letheby, I examined more samples of food than most people. Dr. Letheby was much interested in the subject of milk, and before coming liere to-night, I referred to his original notes on the subject. He examined the milk yielded by two cows for 115 consecutire days.The total solids not fat of the milk of one of these cows never fell belo\v 0 per cent., biit in the second con. in no less than four several occasions, the amount of solids not fat was less than 7.5 per cent. Of the purity of the milk, there was no question. I do not think it possibIe, therefore, to say that because a milk contains 7.5 per cent.: it must he adulterated, although I think there are ninety-nine chances in it hundred that it is. And now, as to the question of nutriment, let me refer to human milk. My first paper on “Human Milk ” appeared in the London Hospital Reports for 1867. I there gave 12 as the average total solids per cent. of healthy human milk, but a larger number of experiments iyould lead me to give quantities varying from 8 to 13 as the normal of the milk of the human kind.Siiice that payer was written, I have examined a large nuiuber of milks takcn from unhealthy women. These analyses are very interesting ;I will only say this much about them, viz., that taking several cases of advanced phthisis, I found 14 per cent., and in one case 14-8 per cent. of total solids, but in spite of this apparent richness the children did not thrive. Conversely, in various neuroses and in cancer, I have found milk with only G.4 per cent. of total solid malter, and in one case actually only 5 per cent., and yet in some of these cases, the children thrived very well. This much appears to me certain, a milk niay appear poor and yet not be poor-it may appear rich and yet not be nourishing.The fact is, the nourishiiig property of milk is in a great measure altogether beyond the scope of a chemical inquiry. I have now notes of over 100 cases where the milk of diseased women Elas been examined, and at the same time careful mcdical examination made of their cases. This appeal to human milk as to composition and nutritive power (for we may hope it is outside the adulterator’s hands) is of importance, not simply chemically, but physiologically. MR. BELL: With regard to the question of milk, we at Somerset House do not subscribe to the limit which is laid down by the Society of Public Analysts. We have laid down no par-ticular limit, as in jndging whether a milk has been watered or not, we take the whole of the constituents into account, and from these we form an opinion as to the genuineness or otherwise of the sample. We have fourid it impossible to adopt the limit laid down by the Public Analysts, because we have taken great trouble to investigate the subject of milk, and we have found considerable variations in its composition, and that no one constituent forms a constant quantity in genuine milk.From the results of our in- vestigation we found that in the case of individual cows, 18 per cent. contained upmards of 14 per cent. of total solids ; that 83 per cent. contained upwards of 12 per cent. ; that 96 per cent. contained over 11 per cent., and that 4 per cent. contained less than 11 per ceut. of total solids.In the case of dairy mixtures we found tlmt 20 per cent. contained upwards of 14 per cent. of total solids, that 79 per cent. Contained upn-ards of 12 per cent., and that 20 per cent. contained less than 12 per cent. total solids. The solids not fat showed also a con-siderable variation. In the case of individual cows we found that 24 per cent. contained over 9.5 per cent. of solids not fat ; that 56 per cent. contained upwards of 9 per cent. ; that 43 per cent. vas under 9 per cent., and that 18 per cent. vas under 8.6 per cent. In the case of' dairy mixtures we found thab 25 per cent. contained over 9.5 per cent. of solids not fat ; that 66 per cent, contaiiied over 9 per cent. ; that 33 per cent. contained less than 9 per cent., and that 12 per cent.contained less than 8-6 per cent. The percentages of fat were equally variable ;for instance, in the case of individual cows, jve found 42 per cent. over 4.0 per cent ; 84 per cent. oxr COO per cent. ; 93 per cent. over 2.5 per cent., and G per cent. uuder 2.5 per cent. In the case of mixed milk from dairies, we found 33 per cent. over 4.0 per cent ; 9s per cent. over 3.0 per cent., and 4 per cent. under 3.0 per cent. In the face of these results, it is obvious that we could not draw a hard and fast line of 9 per cent. of solids not fat, by which to judge as to vhether a milk ms genuine or not. I may here obser-re that in every case, both of individual cows aid of mixed milk from dairies, whether in town or country, the samples represent entire milliings made in the presence of one of the assistant chemists at Somerset House, and the representative character of the samples is assured by the wide range of country, extending from Yorkshire to Devonshire, from Fhich they xere obtained.With regard to intoxicating liquors, when the question has been one of watering, we have simply determined the strength and left the question of undue dilution for the decision of the magistrates. We felt that we had no pwer to lay down any standards of strength, and this being so, we considered it best not to interpose between the analysts and the trade in casesof charges of excessive w,itering. The colouring of spirits with burnt sugar is a practice that has existed for many years, and the practice is a very harmless one.The preparation of brandy, by adding brandy flavouring to plain spirits, and selling the article as foreign brandy, is, in my opinion, an infraction of the Sale of Food and Drugs Act. With respect to salt in beer, we have found in the course of our experience from the analyses of breqing waters and the materials used in brewing, that large percentages of salt may be naturally present in many beers. We indicated as much in our certificate in the first reference case that came before us, but we were very much abused at the time for making such a statement. In many cases, however, that have since occurred, it has been proved that we were right in our warning, but in some instances I have observed successful prosecutions for salt in beer, where from my own knowledge the brewing waters contained large percentages of salt, and if proper precautions had been taken to fix the chlorine, larger percentages of salt would have been found in the beer than represented.In confirmation of the position which we took up, I may mention that I observed recently from an extract of a report of a public analyst, that he found over 120 grains of salt per gallon in a sample of beer, and that he gave it as his opinion that the salt was naturally present, being derived from the brewing water and other materials employed. The Discussion n-as then adjourned. PAGES MISSING FROM 53 TO 76