232 INDUCTION OF 



Organic matter, of whatever kind, spontaneously 

 decaying in the presence of the atmosphere, seldom 

 fails to be covered with fungi and other plants of a 

 low type. 



The ordinary growth of plants has been shown by 

 Muller to be intimately connected with chemical or 

 decomposing changes occurring in the soil. 



The decomposition of carbonic acid and production 

 of organic matter by the leaves of plants has been 

 shown, by Dr. Draper, to involve a decomposition 

 effected in the leaf by light. 



In each of these instances the vital action appears 

 to be the secondary process. The infertile seed 

 decays in the same manner as the fruitful one. 

 Fermentation may take place without any develop- 

 ment of the yeast plant, although less rapidly. Or- 

 dinary putrefaction and decomposition of the soil are 

 not necessarily dependent upon the development of 

 living structures. 



In the phenomena of animal life a similar relation 

 of vital to chemical action may be traced. 



The egg in the act of development absorbs oxygen, 

 and undergoes also, in part, a decomposing change. 



