679 
bearing bacteria have the property of peptonizing the albumens in 
milk. These bacteria survive the process of pasteurization, and are 
thus given a free field for growth, whereas in the raw milk these 
bacteria are largely held in check by the growth of the lactic acid 
forming organisms. This view started with the work of Fliigge and 
has gradually lost ground for lack of clinical and laboratory con- 
firmation. For instance, Park and Holt found that a few cases of 
acute indigestion immediately followed the use of pasteurized milk 
more than thirty-six hours old. Samples of such milk were found to 
contain more than 100,000,000 bacteria per cubic centimeter, mostly 
spore-bearing varieties. The deleterious effects, though striking, 
were not serious or lasting. However, so long as the danger is sus- 
pected it makes us cautious to keep pasteurized milk cold and use 
it promptly. 
If it is important for milk to contain lactic acid bacteria. They 
may readily be added in pure culture after the milk has been 
pasteurized. 
We are told that heating destroys great numbers of bacteria in 
milk, and thus conceals dirt, but Theobald Smith a points out — 
that from a bacteriological standpoint the pasteurization of milk will not con- 
ceal dirt, for the reason that the bacteria that come from the udder or the teats 
will be destroyed, but the bacteria that come from dirt are largely spore-bearing 
bacteria and these survive. I believe that we could control the quality of milk 
quite as well after it was pasteurized by bacteriological counts as before, be- 
cause certain species only would grow or multiply and the indicators would be 
much better than to-day. If we examine a plate made from milk, for instance, 
nobody can tell exactly whether the bacteria are due to dirt or whether they are 
due to the multiplication of ordinary lactic acid bacteria, unless a very careful 
study of that plate be made. As a rule, if nearly all the colonies are alike we 
say that they are the result of. multiplication ; if they are quite different then 
there has been a good deal of dirt added to the milk. Now it seems to me that 
with pasteurization it would be possible to control the dirt in milk much better 
than is done to-day. 
Further, it is said that we must not meddle with nature; that pas- 
teurization is an artificial expedient. Nature never intended milk to 
be collected, transported, and fed to young mammalian animals one 
or two days after it leaves the mammary gland. Even when fresh, 
the milk of one species is not well suited to the needs of the young of 
another species. In the artificial feeding of infants with cow’s milk, 
we are meddling with nature. When artificial feeding is necessary 
we must endeavor to obtain fresh, pure milk. If this is not possible 
the milk should be purified, especially in the hot weather. Each in- 
fant is a law unto itself. 
0 Smith, Theobald : Am. Journ. Pub. Health and Journ. Mass. Assn. Bds. 
Health, vol. 17, 1907, p. 200. 
