480 MANUAL OF MILK PRODUCTS 



from bacteria, but in various ways, chiefly through the food, 

 many kinds of bacteria are introduced into the alimentary 

 canal. In the intestines and particularly in the large intestine 

 some of them find favorable conditions for growth and become 

 established there in large numbers. In the normally nourished 

 infant the bacterial varieties are limited in number and for the 

 most part consist of acid-forming types which by the active 

 fermentation of the milk-sugar furnished in large quantities 

 in the food produce conditions under which bacteria of the 

 putrefactive type are unable to multiply to any extent. The 

 predominance of an acid fermentation in the large intestine 

 produces an acid stool with a characteristic but comparatively 

 unobjectionable odor. As the child gets older the variety of 

 food is greater and the relative proportion of carbohydrates 

 to protein is much reduced. In place of the acid fermentation 

 there is a decomposition of the protein by other bacteria, intes- 

 tinal gas is produced, and the stools become alkaline and fre- 

 quently have a very objectionable odor. In the bacterial 

 decomposition of the predigested protein it is supposed that 

 products of a more or less toxic nature are produced. When 

 the quantity of these products is relatively small, they are dis- 

 posed of through the normal channels and have no appreciable 

 effect. If the excretory system fails to do its normal work, or 

 if the protein decomposition is unusually active, toxic sub- 

 stances accumulate and the symptoms of autointoxication are 

 produced. The production of toxic substances in abnormal 

 amounts may be caused by a combination of circumstances 

 promoting an unusual activity of putrefactive bacteria normally 

 present, or it may be because the bacterial flora of the intes- 

 tines changes and new bacteria are introduced. 



The method of treating this condition by the use of sour milk 

 is based on three conditions which may be stated as follows : 

 (1) it assumes as correct the theory of the production of toxic 

 substances in the intestine by the action of bacteria in quan- 



