CHAPTER V. 



OF REGENERATION. 



IT is impossible to terminate an exposition of generation without 

 saying some words on regeneration, which essentially does not 

 differ from it. We must satisfy ourselves with mentioning 

 the general laws of regeneration, without describing the innu- 

 merable series of particular facts which everybody knows. 



It seems to result from modern micrographical observations 

 that there is identity between primordial phenomena of the first 

 generation of the tissues in the embryon, and those of their 

 regeneration in the adult. In both cases the elements of the 

 newborn tissues are formed by spontaneous genesis in the midst 

 of an organisable blastema. In the animal embryon this forma- 

 tive blastema results from the liquefaction of the embryonary 

 cells : in the adult animal it is formed by the anatomical elements 

 of the conservated tissues. But in both cases the spinal tissues 

 do not appear all at once : they are first of all preceded by a 

 transitory generation of nuclei and of cells called embryoplastic, 

 to which at last succeed the special histological elements. 



The lower an animal is placed in the hierarchy, the greater the 

 degree of regenerative faculty he possesses. In this case there 

 is still physiological confusion. There are no elements specially 

 charged with reproduction. Every histological element pos- 

 sesses then in the state of indi vision, the fundamental properties 

 of nutrition, of development, of reproduction. All the world 

 knows that in the inferior animals we can make with full 



