THE DOGMA OF EVOLUTION 



faces all rationalistic theories when they attempt to 

 start the beginning of action. 



Lamarck begins his theory of variation by an im- 

 portant assumption that organisms can be divided 

 into two classes according as they respond or not to 

 internal stimuli. In the latter class, he places all plant 

 forms and the lower orders of animals. Such forms 

 "live only by the help of excitations which they re- 

 ceive from the exterior. That is to say, subtle and 

 ever-moving fluids, which exist in the surrounding 

 medium, penetrate incessantly these organized bodies 

 and maintain life in them, so long as the state of these 

 bodies permits of it."^ This idea is the same as the 

 theory of Descartes that plants and animals are au- 

 tomata, without feeling or internal impulses, respond- 

 ing only to such external stimuli as heat and electrici- 

 ty; an idea revived by Huxley and in fact the basis of 

 all mechanistic theories which suppose life to be due 

 to physical forces.^ 



As usual, Elliot fails to understand Lamarck's 

 reasoning. He says that Lamarck assumes the me- 

 chanistic position, but not knowing physics, he pos- 

 tulated subtle fluids as caloric and electricity to be the 

 exciting stimuli. He thus allies himself with Driesch 

 and the modern school of vitalists who, by inventing 

 "a factor that is wholly and unutterably new to 

 science," exercise a pernicious and outrageous detri- 



^ Philosophie Zoologique, vol. I, p. 12 [p. 4]. 

 ® See Huxley's Essays on Descartes. 



I 1763 



