quently found these poisonous peptonizing bacteria in practically pure culture. The investigation of the peptonizing bacteria of milk has been continued by Luebbert and also by Vaughan. According to Luebbert (19), these organisms are widely distributed. They have been found to act only on the proteids of the milk, the fat and milk sugar contained in the milk remaining undiminished. He also found the milk cultures of these organisms to be highly toxic. When fed on such milk, guinea pigs died after four days, and puppies after the fourth, fifth, and sixth day, following severe diarrheas. On the other hand, a full-grown dog ate of the milk freely without any bad effect, thus showing that age affords some protection against milk poisoning. Luebbert's results on the toxicogenic peptonizing bacteria of milk have been confirmed by Vaughan (20). According to this author the organisms responsible for cholera infantum are truly pathogenic in that they produce a definite chemical poison, the absorption of which is followed by the symptoms of the disease, and in order to explain the great susceptibility of infants to milk poisoning and the comparative immunity of the adult he has advanced the view that the great susceptibility of children to such intoxications is due to the ease and readiness with which casein is absorbed by the mucous membrane of the intestine of children, and that the casein carries along with it the bacterial cells containing this poison. In the adult, on the other hand, the digestive powers of the stomach are increased and intestinal absorption modified to a corresponding degree. At present practically nothing is known regarding the precise chemical nature of these bacterial poisons, and, as already pointed out by Novy (21), investigations pertaining to a more exact study of the toxicogenic micro-organisms of milk and their poisonous products belong to the future of medical and chemical research. I have been informed by Doctor Vaughan that nothing of any practical importance has been added to our knowledge of the milk poisons during the last few years. PART III. CHEMICAL STANDARDS FOR THE CONTROL OF THE SALE OF MILK. For a number of years the sale of milk in various cities throughout the world has been regulated by law. In this connection various chemical standards regulating the sale of milk have been proposed, based on the results of large numbers of analyses of milk in various countries. I am indebted to L. A. Rogers, Acting Chief of the Dairy Division, Bureau of Animal Industry, U. S. Department of Agriculture, for the following compilation of United States and State standards for milk and dairy products. It will be observed that this compilation was published in 1905. U. S. Department of Agriculture, Bureau of Animal Industry -Circular No. 74. D. E. Salmon, D. V. M., Chief of Bureau.] WASHINGTON, D. C., April 1, 1905. In the table following, prepared under the supervision of Ed. H. Webster, Chief of the Dairy Division, are given the standards for dairy products as proclaimed by the Secretary of Agriculture and as established by law in the several States, so far as obtainable, and revised to date. The percentages stated represent minimum standards in all cases unless otherwise expressed. States not named are understood to have no laws prescribing standards for dairy products. Approved: D. E. SALMON, Chief of Bureau of Animal Industry. JAMES WILSON, Secretary of Agriculture. United States and State standards for dairy products, 1905. a See proclamation of the Secretary of Agriculture, "Standards of Purity for Food Products," Office of the Secretary, Circular No. 10, November 20, 1903. Condensed milk, 28 per cent milk solids, of which one-fourth must be fat. Condensed milk must contain not less than 8.5 per cent fat; evaporated cream containing less than 15 per cent fat must be labeled "An unsweetened condensed milk.' Coffee cream shall contain at least 15 per cent fat, and whipping cream at least 22 per cent fat. f Condensed milk must contain the equivalent of 12.5 per cent of milk solids in crude milk of which 3.5 per cent shall be fats. 9 No thickener allowed. United States and State standards for dairy products, 1905—Continued. Cheese. Fat. Full cream, from 3 milk fat; skim, from milk less than 3 p. c. fat. 18 82.5 15 20 Not over 14 p. c. water. 80 Maxi mum Skim, from skim milk. Skim, from skim milk. Full cream, 30 p. c. fat; a In New York, Ohio, and Wyoming the milk solids of condensed milk must be in quantity the equivalent of 12 per cent of milk solids in crude milk, of which solids 2.5 per cent shall be fat. b Condensed milk must contain 28 per cent milk solids and 7 per cent fat. At the Eleventh Annual Convention of the Association of State and National Food and Dairy Departments, held at Jamestown, July 15-19, 1907, Mr. P. M. Harwood (1), general agent Massachusetts dairy bureau, read a paper entitled "Has the milk standard outlived its usefulness?" He called attention to the fact that on account of the rigid requirements regarding the composition of milk offered for sale in the State of Massachusetts a good many milk producers are being gradually driven from the business for the reason that while milk prices are gradually becoming higher in the cities, the farmer or milk producer does not receive a proportionate amount of the profit accruing from the increased price nor an amount sufficient to compensate him for the trouble and expense growing out of the enforcement of laws regulating the milk standard. He points out that at a recent discussion of the question of the milk standard before the committee on agriculture of the Massachusetts legislature many interesting facts were brought out. It developed at these hearings that the standards now in force-viz, 13 per cent total solids, 3.7 per cent fat, and 9.3 per cent solids not fat, in winter, and 12 per cent total solids, 3 per cent fat, and 9 per cent solids not fat, in summer-are working a hardship on the farmers, and that indirectly not protecting the consumer; that milk contractors and peddlers were using it to their pecuniary advantage, and that the prosecuting officers throughout the State were not rigidly enforcing the law. The author reached the conclusion, therefore, that either the milk standard should be abolished altogether and milk sold upon its merits, or, that if a standard is to be maintained it should be uniform throughout the United States. On account of the very large amount of data on the chemical composition of milk at present available in State and municipal departments and agricultural experiment stations, etc., such a standard could probably be equitably adjusted. Indeed the attempt has been made to do so in establishing the United States milk standard governing the sale of milk under the laws governing interstate commerce. This standard requires a milk to contain 3.25 per cent of fat and 8.5 per cent solids not fat, and, as may be seen from the tables of State and national milk standards given on page 371, it is lower than many of the State standards. According to the secretary of the association of State and national food and dairy departments, the United States standand is being made the basis of standards for all the States. In this connection it is of interest to note that certain high-class dairies throughout the country are prepared to furnish milk of any composition desired, and infants' milk according to the physician's prescription. PART IV-ADULTERATIONS OF MILK. Like many other foodstuffs, milk is subject to many adulterations. These consist (1) in the removal of the cream (skimming) or the addition of skim milk, (2) addition of water (watering), (3) addition of thickening agents, (4) the addition of coloring matters, (5) the addition of certain substances with the view of altering the taste of milk and increasing the total solids, (6) the addition of preservatives (antiseptics). The commonest forms of adulteration are skim ming, watering, and the addition of artificial coloring matters and preservatives, the addition of thickening agents such as chalk, calves' brains, starch, glycerin, etc., having almost passed out of vogue among farmers and dairymen. Indeed it is doubtful whether the (3) form of adulteration was ever practiced to any considerable extent (1). Skimming. This form of milk adulteration is probably practiced among farmers and dairymen to a considerable extent. As its name indicates, it consists in the removal, by means of a separator or otherwise, of a part of the cream. Obviously, skimmed milk contains a smaller percentage of milk fat than normal milk, and it was with a view of correcting and controlling this particular form of adulteration and watering that laws have been enacted in many countries and in many States throughout our own country fixing the amount of milk fat which a milk offered for sale should contain. It will be seen from the compilation of milk standards given on page 371 that the amount of fat required in different States varies from 2.4 to 3.5 per cent. All things considered, it seems reasonable to require that all milk offered for sale should contain at least 3.25 per cent of fat, although it should be borne in mind, of course, that unadulterated milk, especially of certain breeds of cattle, sometimes contains less than this amount of milk fat. The color of skimmed milk is also more or less characteristic, tending more to dead white or bluish white than normal milk, which is distinctly yellowish white in color. Watering. The addition of water to milk is probably the commonest practice in milk adulteration. Obviously this is done in order to increase the output of the herd. The effect of watering is to alter the physical properties and chemical composition to a greater or less degree, depending on the quantity of water added. The addition of water to milk has been found to lower the specific gravity and elevate the freezing point of milk. It also lowers the index of refraction and probably the viscosity. It causes diminution in the amount of fat, total solids, and ash. Ordinarily it is not a difficult matter to determine whether a given sample of milk has been watered. This is done by comparing its specific gravity and refractometer reading, together with the amounts of fat, total solids, and ash, with those of normal milk or with standards which have been based upon the results of thousands of analyses and years of experience with the milk of different herds of dairy cows and that produced in different countries. In the detection of watered milk advantage is also taken of the fact that natural waters frequently contain substances not ordinarily present in milk, such as nitrates and nitrites. If these substances are found in a sample of milk the chances are that water |