22 BULLETIN 342, U. S. DEPARTMENT OF AGRICULTURE. 
pasteurized at 145° F. for 30 minutes does not undergo any appreci- 
able chemical change. He found that soluble phosphates do not 
become insoluble, that the albumin does not coagulate, and that when 
higher temperatures are used chemical changes do occur. He also 
developed the fact that 5 per cent of the albumin is rendered insoluble 
in milk heated for 30 minutes at 150° F., while at 160° F. 30.78 per 
cent of the albumin is coagulated. Further evidences that low-tem- 
perature pasteurization does not injure the digestibility and nutritive 
value of milk are shown by the results of feeding experiments with 
babies. According to Weld (31), a number of babies that were fed 
raw milk and pasteurized milk showed only a slight difference in 
the average net daily gain in weight during the feeding period. The 
slight difference was in favor of pasteurized milk. Hess (21), how- 
ever, has found that milk pasteurized for 30 minutes at 145° F. may 
cause, in infants, a mild form of scurvy, which yields readily to so 
simple a remedy as orange juice. 
High-temperature pasteurization of earlier days must not be con- 
fused with low-temperature pasteurization of the present day. Many 
of the objections which have been raised to pasteurization have been 
founded on the observation of milk heated to high temperatures. 
The fallacy of the objections to pasteurization have been shown, 
however, through scientific research in the last few years, and as a 
result the value of the process has.been firmly established. 
PASTEURIZATION AND VITAMINS. 
The discovery of vitamins within recent years has shown how im- 
possible it is to estimate nutritive requirements solely in terms of 
digestible protein, carbohydrate, fat, and inorganic salts. But little 
is known of the real chemical nature of vitamins, except that they are 
necessary for normal growth and health. Three vitamins are now 
recognized, known as vitamin A (soluble in fat) and vitamins B 
and C. (soluble in water). Most authorities now agree that fat- 
soluble A and water-soluble B are essential for growth, and water- 
soluble C, the antiscorbutic vitamin, may also play a part in this 
relation. 
Because of the limited character of the infant’s diet the vitamin 
content of its food is more important than that of the adult’s, as the 
latter has a great variety of foods. Fortunately, milk has been 
found to be a food containing the three vitamins and the effect of 
pasteurization on the vitamin content is of importance. 
Fat-soluble A and water-soluble B have been found to be quite 
resistant to heat, and it is agreed that pasteurization has little or 
no effect upon them. The antiscorbutic vitamin C, however, is quite 
sensitive to heat above 122° F. While the destruction of this vita- 
