627 
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- 
jtected, it makes us cautious to keep pasteurized milk cold and use 
it promptly. 
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 infant is a law unto itself.' 
Pasteurization of all of the milk supply of a communit}^ may not be 
desirable. The clean, fresh milk, free from contamination, may not 
need it. Special cases may require raw milk, but the general public 
should be protected against the old, dirty, and uncared for milk which 
forms the bulk of the supply of large cities. 
The heating must be done intelligently and under the supervision oi 
the health officer. After heating, the milk is just as liable to serious 
contamination as before if not more so. It must therefore be care- 
fully guarded, kept cool, and promptly delivered. 
a Smith, Theobald : Am. Journ. Pub. Health and Journ. Mass. Assn. Bds. 
Health, vol. 17, 1907, p. 200. 
