﻿LIVING PLANTS 



Physical 

 features of 

 cell walls 



mental substance of the wall iscarbohydrous, 

 and in the animals nitrogenous. 



The carbohydrous investment of organisms, 

 chemically considered, is probably always 

 some form of cellulose. There are primary 

 and compound celluloses, and various modifi- 

 cations of these. In some instances nitrogen 

 seems to be associated with the cellulose, as 

 Winterstein has recently claimed in the case 

 of certain fungi, but of the nature of this asso- 

 ciation nothing is definitely known ; the facts 

 can have little bearing ui3on the fundamental 

 proposition here laid down. 



The nitrogenous investment is chemically 

 always of the nature of a non-protoplasmic 

 proteid, of very complex molecular structure, 

 undoubtedly varying much in different organ- 

 isms. 



Both the carboh3alrous and nitrogenous 

 vestural substances are very likely chemically 

 analogous, as maintained by Elsberg some 

 fifteen years ago. Quite recently Cross and 

 Bevan in their treatise on cellulose suggested 

 that the substance of the proteid cell wall 

 "may prove to be of similar carbon configur- 

 ation to that of cellulose." 



But in physical characters the two kinds of 

 cell investiture are widely different, and espec- 

 ially so in their degree of elasticity. Carbo- 



