METHODS 



131 



in nature, we have great difficulty in finding them. What 

 Cope calls cases of physiogenesis are often instances of 

 the direct action of the medium on the constituent cells of 

 an animal instead of direct action on its mechanism as a 

 whole. But the cell is a colloid mechanism and, if the cell 

 receives an impression as a mechanism, the variation resulting 

 from it in its chemical elements is a direct adaptation ; it 

 is cellular cinetogenesis, but it is cinetogenesis all the same. 



The only instance of real physiogenetic action is that in 

 which the agent determining the vital activity is a dissolved 

 (and not colloid) chemical substance, able to influence 

 directly the chemical elements which enter into the consti- 

 tution of the protoplasm. Such, for example, is the case of an 

 injection of morphine into a mammal ; and yet an isolated 

 mammal can habituate itself to morphine, which gives the 

 phenomena a Lamarckian look. 



This result comes from the reversibility established 

 between the chemical phenomena and the colloid states of 

 the protoplasm a reversibility which we have already 

 shown from the relations of cause and effect existing 

 between colloid equilibrium properly so called and the 

 chemical equilibrium between the particles of the colloid and 

 their solvent. 



A few words will sum up these questions of equilibrium 

 between mechanisms of different dimensions. They will give 

 us a more scientific explanation of individual adaptation 

 than that which is drawn from adaptation, after the fact of 

 Natural Selection, to variations of the smallest independent 

 units. 



