VITAL PHENOMENA. 189 



disorganized after having gone through what we may 

 call an ideal trajectory. This march in a fixed 

 direction with its points of departure, its degrees, and 

 its termination, is a repetition of the path that the 

 ancestors of the living being have already followed. 



Here, then, is a characteristic fact of vitality, or 

 rather there are two facts. The one consists in this 

 morphological and organic evolution, the negation of 

 immutability, the negation 6F tne indefinite main- 

 tenance of a permanent state or form which is 

 regarded, on the contrary, as the condition of inert, 

 fixed stable bodies, eternally at rest. The other 

 consists in the repetition, realized by this evolution, 

 of the similar evolution of its ancestors ; this is a 

 fact of heredity. Finally, evolution is always in a 

 cycle that is to say. that it comes to an end which 

 brings the course of things to their point of departure. 



This kind of internal activity of the living being 

 is so striking, that not only does it serve us to 

 differentiate the living being from the inert body, 

 but it gives rise to the illusion of a kind of internal 

 demon, vital force, manifested by the more or less 

 apparent acts of the life of relation, of the motricity, 

 of the displacement, or by the less obvious acts of 

 vegetative life. 



Vital PJienomena regarded as a Reaction of the 

 Ambient World. Their Twofold Conditioning. In 

 reality, as the doctrine of energetics teaches us, the 

 phenomena of vitality are not the effect of a purely 

 internal activity. They are a reaction of the environ- 

 ment. "The idea of life," says Auguste Comte, 

 " constantly assumes the necessary correlation of two 

 indispensable elements : an appropriate organism 

 and a suitable environment. It is from the reciprocal 



