PSYCHIC ADAPTATION 101 



vascularity of the encephalus, the quality of the 

 nutritive plasma, the amplitude of the peri-vascular 

 lymphatic sheaths of the grey substance, and even 

 the state of the vasomotor innervation, by means of 

 which is regulated the quantity of blood that pene- 

 trates into each encephalic region through the 

 solicitation of the will and the influx of the 

 attention." 



The attentive study of these grand conclusions 

 illuminates the history of humanity and explains 

 the alternations of civilisation and decadence. 

 Such contrasts, which may be explained as a 

 natural and necessary consequence of progress, as 

 a species of cyclic movement, obey other laws, and 

 the explanation of yesterday, and even of to-day, 

 is completely gratuitous. This flux and reflux in 

 civilisation are inadmissible as an essential condi- 

 tion in it ; that would be tantamount to ignoring 

 or denying the spirit of the law of evolution. From 

 the first protist to man, evolution has always 

 followed an ascending course, all the more rapid, 

 the greater the differentiation in the organisms. 

 Why should humanity have these oscillations ? 



Organisation in this case follows rather a uni- 

 formly accelerated movement, as it starts from the 

 law of consistency of form, with regard to simplicity 

 of structure ; whilst, the higher the organisation, 

 the more rapid the adaptation. Therefore, in 



