214 NUTRITIONAL PHYSIOLOGY 



charge must now be considered. This is the production in 

 later life of arteriosclerosis. 



The saying is current among physicians that "a man is 

 as old as his arteries." It is certainly a fact that the 

 stiffening of these vessels is a chief cause of malnutrition 

 and waning power in the tissues of the aged. If arterio- 

 sclerosis sets in prematurely, other features of a senile 

 decline may be expected. Metchnikoff has sought to 

 establish a connection between the overconsumption of 

 proteins and early loss of elasticity and adaptability in the 

 human circulatory apparatus. Such a connection has 

 long been granted to hold for alcohol We seem brought 

 to admit that this serious impairment of efficiency may 

 spring from intemperance in eating as well as in drinking. 



The postponement of old age by frugality in feeding 

 seems in a measure possible. Yet we must remember that 

 self-denial in this respect may defeat its own end, since it 

 may too greatly weaken the digestive capacity. An al- 

 ternative to low diet, it has been suggested, may be found 

 in the deliberate regulation of the bacterial conditions in 

 the intestine. The claim is made, and seemingly with good 

 reason, that a harmless type of fermentation may be en- 

 couraged with the result that the undesirable decompo- 

 sition may be prevented. This is the theory underlying 

 the various modes of sour-milk treatment so much in 

 vogue during the last five years. Lactic acid in moderate 

 amounts appears to be quite devoid of danger to one's 

 health. Its presence in the canal is hostile to the develop- 

 ment of the organisms, which cause radical putrefaction 

 of the proteins and definite auto-intoxication. A domi- 

 nant acid fermentation may be secured either by the 

 taking of sour milk (kephir, koumiss, matzoon, etc.) or by 

 swallowing from time to time cultures of the lactic organ- 

 isms, together with sugar for them to work on. 



The comparative harmlessness of even extreme constipa- 

 tion when associated with sparing feeding and active 

 absorption has been granted. Such inaction of the intes- 

 tine when it accompanies more liberal indulgence in food 



