100 MAN --AN ADAPTIVE MECHANISM 



him. The fundamental action of bacterial life is the 

 resolution of dead organic matter into its inorganic 

 elements. Were animals and plants deprived of these 

 natural scavengers, the earth's surface would soon be 

 choked with an accumulation of the dead which would 

 ultimately destroy all vegetable and animal life, includ- 

 ing man himself. 



There are many instances of beneficent bacteria 

 without the body of man. Such, for instance, are 

 the bacteria which assist in replenishing worn-out 

 soil by absorbing nitrogen from the air and offering 

 it in available form to the growing plants ; the bac- 

 teria which accomplish the fermentation of wine, which 

 ripen cheese and which put the flavor into butter, 

 which tan hides and which cure tobacco. Within 

 the body of man ample opportunity is provided for 

 the useful domestication of bacteria by the quantities 

 of dead matter and deleterious poisons constantly 

 being thrown off by the living tissues. Wherever on 

 or in the body there have constantly throughout 

 phylogeny been found unresolved organic elements of 

 food, of secretions or excretions, there are found also 

 specific types of " parasitic" organisms evolved to 

 utilize the debris which would otherwise have accumu- 

 lated and hindered some important function. Thus 

 we have bacteria which reside normally in the oily 

 secretion of the skin, the waste matter of the in- 

 testines, the mucous secretions of the mouth, the 

 nose, the throat, the lungs and the genital tract our 

 phylogenetic scullery maids. 



Of all these scavengers the most useful and perhaps 

 the least appreciated are the gaso-genetic bacteria, 



