CHAPTER IX 



CHEMICAL ACTIONS ON PROTOPLASM 

 AND ITS COUNTER-ACTIONS 



HITHERTO we know living protoplasm as a 

 complicated system of colloidal substances 

 possessing a highly developed structure, and ruled 

 by a great number of catalytic reactions. The 

 complex of these reactions is able to maintain the 

 cell-structure, to take up substances from outside 

 the cell to digest them and to gain from them 

 both energy and cell-substance for growth. 



We have not yet completely treated of the 

 mutual chemical interchange between the outer 

 world and living cells. This influence consists in 

 something more than in taking up food and giving 

 off excretion substances. The whole life-process 

 depends to an enormous extent upon external 

 chemical influences. Minute traces of iron salts, 

 scarcely to be ascertained by chemical analysis, 

 possess the power of greatly accelerating growth 

 and respiration. Life can be destroyed by other 

 substances in quantities which are infinitely 

 smaller than the mass of protoplasm which the 

 deadly substance can injure. Such influences 



