THE ENERGY OF EVOLUTION. 477 



been the cause of this change of opinion in Huxley's 

 mind, the cause which has produced a similar change 

 in the minds of many men, has been the discovery of 

 means of producing in the laboratory numerous organic 

 compounds, which, it had been previously supposed, 

 could not be produced excepting through the action of 

 living things, vegetable and animal. But it has been 

 shown that all of these substances are the result of the 

 running down of protoplasm, and are, hence, catage- 

 netic, and not anagenetic. 



That the catagenetic energies, whether physical or 

 chemical, tend away from life is clear enough. Thus 

 molar motion, unless continuously supplied, or directed 

 by a living source, speedily ceases, being converted by 

 friction into heat, which is dissipated. The same 

 is true of molecular movements, under the same con- 

 ditions. Chemical reactions, which are fundamental 

 in world-building, result in the production of solids 

 and the radiation of heat. This is the general result, 

 although in the process, as it occurs in nature, irregu- 

 larities occur, owing to local and temporary elevation 

 of temperature. This arises from the decomposition 

 of organic substances, which liberates heat ; the oxy- 

 dization of carbon, which owes its position as a ter- 

 restrial element to vegetable and animal organisms ; 

 and the access of heat from the interior of the earth, 

 or from the sun's rays. Finally cosmic creation in- 

 volves the perpetual radiation of heat into space, and 

 the gradual reduction of all forms of matter to the 

 solid state. 



The endothermic chemical reaction, where inor- 

 ganic matter undergoes a change of molecular aggre- 

 gation the reverse of that just mentioned, with the ab- 

 sorption of heat, as in the case of several nitrogen 



