DEVELOPMENT OF CITY MILK SUPPLY PROBLEMS 39 



marked improvement in the health of ailing infants when fed 

 upon sour milk is commonly attributed to a difference in the 

 kinds of germs present in the milk consumed before and after 

 the improvement with a corresponding difference in the 

 character of the changes produced in the milk by these germs. 



So far as studies have been made, there is shown surpris- 

 ingly little qualitative difference in the bacterial flora of the 

 ordinary public milk supply when carrying a high germ con- 

 tent and the flora of the milk which has acknowledged ther- 

 apeutic value in the treatment of sick babies. There are, of 

 course, quantitative differences in that the total number of 

 germs in the therapeutic milk is much higher and this in- 

 crease in numbers is largely in germs with marked acid-form- 

 ing tendencies. 



Too little is yet known of the chemical products of bacterial 

 action in milk to justify conclusions, but the known ability 

 of milk compounds to absorb or otherwise neutralize small 

 amounts of bacterial by-products suggests that many of them 

 may be cared for in this way. Acid is the most evident by- 

 product of this bacterial action but this is most abundant in 

 the therapeutic milks. 



Failing to find a satisfactory explanation for the illness of 

 children in the number of germs involved or in any of their 

 recognizable by-products, it seems logical to seek for other 

 explanations of the constantly observed coincidence of high 

 germ content milk supplies and baby sickness. 



A part of the diarrheal diseases of children is undoubtedly 

 due to the action of specific dysentery organisms. No tech- 

 nique is available by which the presence of these organisms 

 in milk can be readily determined but pasteurization offers 

 the same protection against them as against other pathogenic 

 organisms. 



Experience in the feeding of domestic animals has abun- 

 dantly demonstrated that an animal accustomed to a uniform 

 diet is markedly disturbed by sudden changes in its ration. 

 It is an axiom in the feeding of dairy cows that changes in 

 the amount or character of their ration should be made 

 gradually. The gratifying improvements which have followed 



