MILK AS A DISTRIBUTER OF DISEASE 229 



as to whether he is careful or careless in handling it. 

 In general it is well not to buy milk from a dirty or care- 

 less milkman, for such a man is much more likely to sell 

 milk that is a source of danger. For this reason milk 

 distributed in glass bottles is more reliable than that 

 distributed from metal cans. 3. Practically all of these 

 dangers may be avoided by the use of pasteurized, con- 

 centrated, or certified milk. The latter is a higher grade 

 of milk, coming from special farms, and should have a 

 certificate from a medical commission. They cost more 

 than the ordinary grade, but are safe to use, and may be 

 given to infants without fear of contagious diseases. In 

 general, then, the first factor to be considered in guard- 

 ing the family from disease through milk is the obtaining 

 of the supply from reliable sources only, even though the 

 price may be higher. This will give a more reliable prod- 

 uct, one that is more valuable as a food and less liable to 

 produce disease. 



But in many households this may not be possible, and 

 the family may be obliged to depend upon the ordinary 

 milk supply without any knowledge of its source. What 

 should be done under these circumstances? Such milk 

 can be rendered harmless, so far as concerns the diseases 

 referred to, by the processes of sterilization mentioned on 

 another page. Since milk from an unknown source may 

 be rendered safe for use in this way, it is easy to under- 

 stand why sterilization has in recent years come to be 

 so widely adopted. The same end is more satisfactorily 

 reached by pasteurization. 



Every housekeeper will ask, however, whether such a 

 precaution is necessary under ordinary conditions. This 



