No. 629] 



BEHAVIOR AND ASSIMILATION 



511 



tion is an autocatalytic process ; because the end products 

 of assimilation act as catalytic agents for their own syn- 

 thesis. In green plants and the independent bacteria it is 

 also an endothermic process, because the end products of 

 assimilation have a higher energy content than the com- 

 pounds from which they are constructed. As an illustra- 

 tion of an autocatalytic reaction between inorganic com- 

 pounds, the formation of Millon's reagent may be cited. 

 When mercury is dissolved in nitric acid, a certain 

 amount of nitrous acid is formed. Nitrous acid is a 

 catalytic agent for the solution of mercury in nitric acid, 

 and therefore for its own production. To quote from 

 Troland ('17, p. 337), w^io has discussed the theory of 

 autocatalysis : 



matter as a n.niiilcx mixim.' nf substances suspended by colloidal sub- 

 division in WMKT. ^iiMv ilic.v i~ iiM fvidenec that the individual colloidal 



Livable that these bodies, whicli are the real cheniieal units in proto- 



lii other words, the process of assimilation is like crys- 

 tallization from a supersaturated solution by seeding 

 with a crystal. The following quotation from Findlay 

 ('04, pj). ()7 ()8) throws light on this process: 



