from that in which they exist in body protein, they must be of inferior nutritive value, since large quantities must be broken up in order to yield that quantity of certain units necessary for the construction of animal protein. Such inferior proteins occur among the plants. Plant proteins are eaten by the ox and are reconstructed into beef proteins, with the oxidative elimination of the excess of chemical units which are unnecessary for the structure of the animal cell. In this way beef protein attains a higher biological value for the nutrition of man than is possessed by vegetable proteins." Owing to differences in their amino acid make-up the amount of different proteins which must be eaten to protect the body from protein loss varies; about 30 grams of meat or milk protein and as much as 76 grams of bread protein or 102 grams of Indian corn protein being required.

The author calls attention to the power of protein to increase greatly the heat production of the body by stimulation, stating among other things that "individuals maintained on a low protein diet may suffer intensely from the cold. A good piece of beefsteak or roast beef will put the heat production on a higher level, and a person going out of doors on a cold day after a meal high in protein does not feel the cold. For the same reason, on a hot summer day, meat will be avoided."

One chapter is devoted to the diversity of dietary habits in different parts of the world, attention being called to the diet of the Eskimo, which at times contains as much as 9 pounds of meat per person daily, the low protein diets of the inhabitants of India, China, Japan, and the Philippines, and the standard European diet of Voit.

The author emphasizes the importance of considering the cost of foods in relation to their nutritive value and much information is given regarding the cost of nutrients as furnished by different food materials and in the final chapter data collected by F. C. Gephart regarding the cost and nutritive value of the portions of various foods sold from the counter of a well-known chain system of restaurants in New York and other cities are included which serve to emphasize the extreme variability of the purchasing power of money when expended for food. In general, the author proposes that foods should be sold on the basis of their energy value and of the proportion of the total energy contributed by proteins. "The proteins of the foodstuffs should be labeled A, B, and C according to their physiological value, and to group D might belong gelatin and some other proteins which can not replace the body protein that is continually wearing away." The relative value of different

proteins, as determined by the products which they yield on hydrolysis, as well as other recent work on the nature and functions of protein, are discussed.

As the author points out, "since the efficiency of labor depends upon its [i. e. of the body] energy and constant repair, it is certainly of no small moment that the citizen should know how best to maintain the machine at a maximum of efficiency. Not only that, but in times of trouble he should know where to turn to find nourishment in the form which is best and cheapest. If, through the medium of the schools and the press, everyone knew that a man of sedentary occupation required 2500 calories and a laboring man 3000 calories and more, no one suffering from want would spend his money for a can of tomatoes which is little else than flavored water.

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"It has been estimated that a family of 5, including the father, a clerk, the mother who does the housework, and 3 children, 9 and 6 years and 1 month old, respectively, requires 7750 calories per day." Data are presented showing the cost of a diet sufficient to supply this energy, 5 per cent of the total coming from animal proteins of grade A and 10 per cent from vegetable proteins of grade C (bread). The necessary protein to supplement the bread would be supplied by four-fifths pound salt codfish, three-fifths pound smoked ham, four-fifths pound cheese, two and one-half pounds milk, one and one-half pounds loin pork, one and one-third pounds of mutton, one and one-fourth pounds cod steak (fresh), one and one-third pounds sirloin beef, or one and one-half pounds turkey. According to the prices of foods in the New York markets. January 28, 1913, the cost of the ration would vary from 47 cents with bread and salt codfish to 78 cents with bread and turkey.

"If corn meal, oatmeal, dried beans or rice had been used instead of bread, these prices would have been lower, whereas potatoes would have slightly increased them.

"These figures are for the great staples of diet.

It is obvious that when more than an average of 8 cents is expended for 1000 calories of nutriment, the diet must include luxuries."

The author estimates that three servants will double and six servants treble the food bill given above. "Whatever is spent above these amounts is paid for waste or for nonessentials in the form of flavors of high price. High cost may also be due to carnivorous indulgence approximating that of the Eskimo. . It is not probable that the food values actually consumed are very different in the various wellnourished families. Only the cost can vary enormously."

PASTEURIZATION AS A PUBLIC HEALTH MEASURE

C. E. HILLIARD

Professor of Biology and Public Health, Simmons College

Foods of animal origin that are consumed in the raw state must be reckoned among the important distributors of disease.. Whatever the art of cooking may contribute to flavor and digestibility of foods, it is preeminently a health measure. Prof. William T. Sedgwick goes so far as to say that "probably the greatest sanitary step ever taken was the application of high temperatures to the preparation of food." When we consider that the primary source of disease germs is the animal body, chiefly the human body, it is not difficult for us to picture the way in which germs travel from person to person within or upon the unsterilized vehicle, food. It is true that many of the bacteria will survive prolonged heating at cooking temperatures, but, fortunately, almost none of the pathogenic organisms exhibit such resistance.

Milk was certainly intended by nature to be consumed in the raw state, but in the natural order of things the source of supply and the consumer were very close together. Nothing can ever rival breast-fed milk as a perfect pure food for infants. As man has commercialized cow's milk, however, the pure comparatively germ-free product becomes exposed to all sorts of contaminations. The market has been driven further and further from the source of supply, and the number of persons coming in contact with the milk, the different containers it must pass through, and the time consumed in its transportation have all contributed to its germ content potential disease germs, and have made it a very questionable food product, especially in large cities.

Picture, for example, the difficulties involved in protecting a supply like that of New York City; literally a vast river of 2,000,000 quarts of milk, coming from a radius of 400 miles, arising from 44,000 sources situated in seven different states, flowing into a number of huge reservoirs which serve as the centers of distribution within the city. Constant supervision of such an area is almost impossible.

It is impractical to try to estimate how many people are employed in handling this supply, but it is certainly in the hundreds of thousands. One person in every three or four hundred of the average population suffers each year from typhoid fever, and so each year it is highly probable that some of this supply comes in contact with incipient cases of this disease. Add to this danger the more serious menace from the

typhoid germ "carrier," i.e., the healthy, unsuspecting harbinger of the disease germ, and we begin to realize why we so frequently see accounts of milk-borne epidemics of typhoid fever in the newspapers.

The danger from tuberculosis is twofold; the cow, as well as man, is a source of tubercle bacilli. The former will in time be effectively controlled by eliminating the tuberculous cattle, but it is more difficult to protect against infection by human beings.

Other diseases that may be transmitted by milk are diphtheria, scarlet fever, epidemic sore throat, and various intestinal disorders of infants and children. The above list is not complete, and if we could take the space to give some figures on the amount of sickness and death caused by the drinking of raw milk, no one would doubt the potential danger lurking in the opaque and apparently pure fluid. Thanks to the advancement of science, the day of unheated milk as a food product in America is rapidly passing.

It was about 1870 that Louis Pasteur, studying the causes of deterioration of wines and beers, discovered that the cause of these "diseases" was living microorganisms, and showed that they might be destroyed by subjecting the liquors to the temperatures of 158° F. to 176° F. for a few minutes. The process was called "pasteurization" for the great man who originated it. The term now usually refers to the practice of partially sterilizing milk by heating it to temperatures well below the boiling point of water, and cooling it rapidly to 50° F. or lower.

The application to milk was first tried in Denmark to improve the flavor of butter and to prevent tuberculosis developing in calves to whom the skimmed milk was fed. It was next employed secretly by dealers to enhance the keeping qualities of milk. It was looked upon with disfavor by health officials who believed that it was simply a way of concealing careless production and handling.

With the growth of knowledge of the sources and modes of infection, and expecially of the role of milk, a few sanitarians advocated pasteurization as a public health measure to be applied to large city supplies, and, although they met with serious opposition which came, curiously enough, from the medical profession, today the practice is so well recognized that we find it used as an advertising asset by many milk companies, and official regulation is requiring the heating of all milk except the very highest grades. In New York City 99 per cent of the entire supply is pasteurized, a condition the more remarkable since five years ago only 7 per cent was heated. In 1913 the amount had risen to 75 per cent of the total. In 1913, 80 per cent of Boston's daily supply of

390,000 quarts was pasteurized, and similar figures might be quoted for many other large American cities.

This progress has not been made without serious opposition and does not go unchallenged even today. Physicians claimed that heated milk caused rickets and scurvy. Perhaps the final word has not been said on this point, but the evidence does not support the charge. Rickets seems to be a disease of defective alimentation, while scurvy is remedied by giving with the food the juice of fruits, as orange or pineapple. The claim that malnutrition follows the use of this food by infants and children lacks evidence unless we take occasional exceptional instances.

Pasteurized milk is recommended today by most pediatrists especially in the summer time, and we find that most of the milk dispensed at the baby milk stations is heated milk. Nathan Straus began distributing pasteurized milk to babies in New York City in 1893. The first year only 34,000 bottles were distributed, while in 1906 the amount had risen to 3,140,252 bottles. The results more than justified the experiment, and now the gospel of safe heated milk versus questionable raw milk has spread through the land.

A comparison of what baby will do on the two kinds of milk is given by Mr. George M. Oyster who has distributed milk in Washington, D. C. under careful medical advice. There were three groups of babies; one using raw milk, one pasteurized milk, and a third using pasteurized and raw milk intermittently. In the first group of 351 babies, a net gain in weight per baby per day of 0.4030 ounce was shown. The 557 babies using pasteurized milk gained in weight an average of 0.4077 ounce, showing an excess over the first group of 0.0047 ounce per baby per day. The third group used raw milk part of the time and pasteurized milk part of the time. All the other factors remained the same. While on raw milk each baby gained 0.4312 ounce, and during the time they used heated milk, gained 0.4607 ounce per day, or an excess in favor of the pasteurized milk diet of 0.0295 ounce per baby per day.

Some other interesting data on the relative merits of raw as compared with heated milk for children is found in the case of the death rates in New York among young children in the city's care. The milk used throughout came from a selected herd. During the three years 1895-1897, 1509 deaths occurred among 3609 children while using raw milk, or 41.8 per cent died. With no other change except the introduction of pasteurized milk, between 1898 and 1904, 1349 deaths occurred among 6200 children, or 21.75 per cent died. These figures speak eloquently for the use of pasteurized milk for babies and children.