INFECTIONS OF THE DIGESTIVE TRACT 75 



haps annoying mental and physical fatigue. Moreover, 

 these persons have found by experience that they must 

 be more careful than formerly in respect to food and 

 drink, emotional and sexual excitement, etc. Dining 

 out and the use of alcoholic drinks are indulgences 

 quickly followed by unpleasant consequences. Physical 

 exercise out of doors becomes more and more a necessity 

 to this group of individuals. They are conscious that 

 it requires careful living to keep them in a condition 

 compatible with the performance of their duties. 



Period of Senescence. The age of an individual 

 must be measured rather by the physiological potential 

 of his cells than by the number of his years. There are 

 men who at seventy have cells with functional capacities 

 superior to those of other men who are little beyond 

 forty, and who show their superiority in the ability to 

 work without fatigue, to digest without any conscious- 

 ness of the digestive processes, and to make large out- 

 puts of mental and muscular energy without ill effects. 

 These persons retain soft arteries, are well nourished, and 

 exhibit little atrophy of the subcutaneous areolar tissues, 

 and hence show little wrinkling of the skin. They are, 

 in short, candidates for an advanced age. 



If we examine the intestinal bacteria and the urine of 

 such people, we find conditions wholly in harmony with 

 the unusual preservation of general functional powers 

 and with the freedom from signs of disordered digestion. 

 The faeces contain an abundance of viable bacilli of the 

 B. coli group and the putrefactive anaerobes are few 

 in number. Analyses show the presence of mere traces 



