CHEMICAL CHARACTERS OF CELL 39 



cyanogen was declared by Pfltiger to be half-alive, 

 but the phrase was rhetorically used, for what is 

 really meant is not by any means what might be 

 taken to be meant by the phrase in question. To 

 explain the matter fully would lead one too far 

 into the paths of chemistry, but this at least may 

 be said that no chemist would assert that cyanogen 

 or any of its compounds was in any way even on 

 the road to being what may be properly understood 

 to be a living organism even of the most lowly 

 character. 



Hertwig l says that the work of the investigator 

 of the peculiar problems of life begins where that 

 of the chemist comes to an end. " Over the growth 

 of the chemical molecules is placed the growth of 

 the cell, and over this again the growth of plants 

 and animals with their unions of millions and 

 milliards of different cells. Chemical knowledge 

 as it exists at present has nothing to do with that 

 new world of organised substances in which the 

 manifestations of life are first made obvious." 



The living cell, as we have seen, is composed of 

 comparatively few elements. It derives its food 

 from all sort of things and from this food it builds 

 and rebuilds its own substance, bending the ma- 

 terials which it assimilates to its own uses and 

 purposes. This process of assimilation is no doubt 

 1 Allegemeine Biologie, 2 te. ed., 1906, s. 19. 



