TRANSPORTATION PROBLEMS I 85 
likely, supplied chiefly with lactic bacteria. Sterilized milk, if 
it does retain a single spore, will be in time, more dangerous than 
ordinary fresh milk. For this reason, among others, this practice 
of treating milk to superheated steam for the purpose of absolute 
sterilization has disappeared. 
The term sterilization is sometimes applied to the simple 
boiling of milk. ‘This was recommended by physicians long before 
its real significance was understood and has been very widely 
used in all civilized countries. Its ease of application explains the 
reason for its popularity. It is only necessary to place the milk 
upon the stove and allow it to come to a boil, and the end is 
reached. In some countries very little milk is used without such 
previous boiling, and even the children are taught in school that 
it is dangerous to drink milk without such treatment. The pur- 
pose aimed at in this wide use of boiling, which is commonly, 
though not properly, called “sterilization,’”’ is simply to destroy 
the danger of distributing diseases by the destruction of patho- 
genic bacteria. This purpose js certainly achieved, for the boil- 
ing temperature does destroy all the pathogenic bacteria which 
are likely to be in milk, since none of these are spore producers. 
But several practical objections have arisen: 
1. The bacteria spores are not destroyed, and such milk, if 
kept, will surely undergo a fermentation. But this is of little 
importance if the boiled milk is to be used at once. 
2. The milk acquires the well-known taste of boiled milk 
which is, to most people, unpleasant. People are willing to take 
boiled milk upon an emergency as an invalid diet, but few will 
continue its use. The taste is not enjoyed, and, rather than drink 
boiled milk, the majority of people will give up drinking milk alto- 
gether. This is certainly not desirable, since milk forms one of 
the best and cheapest foods. Any treatment which greatly 
reduces the amount used is, in itself, undesirable; and the practice 
of boiling milk certainly does reduce the amount used. 
3. Milk treated to a temperature as high as boiling becomes 
