THE BACTERIAL CONDITIONS IN THE DIGEST- 

 IVE TRACT DURING CHILDHOOD, ADOLES- 

 CENCE, ADULT LIFE, AND SENESCENCE 



THE bacterial conditions in the digestive tract between 

 the period of childhood and that of old age differ in 

 health so considerably from the conditions that exist 

 during the period of milk feeding that they call for sepa- 

 rate consideration. The difference depends mainly on 

 the character of the diet, which grows more varied at 

 the end of the milk period and stays so throughout the 

 remainder of life. With the more varied diet comes 

 increased opportunities for the entry of many sorts of 

 bacteria into the digestive tract. It is impossible to 

 briefly picture the bacterial conditions in the digestive 

 tract in such a way as to take account of the many 

 individual peculiarities which are met, but fairly typical 

 descriptions are possible. It must be distinctly under- 

 stood that these descriptions are based on well-cared-for 

 individuals and not on the study of neglected persons 

 or persons following peculiar occupations which subject 

 them constantly to irregular conditions of life. 



Period of Childhood and Adolescence. The bacterial 

 conditions in childhood * and during adolescence differ 

 somewhat from those of later life, and it is essential to 

 recognize these differences in any discussion of such 

 conditions. During normal childhood and adolescence 



