Chap, ni.] OF GROWTH IH" 'THE ANIMAL KINGDOM. 289 



It woTild seem at the first glance as if the question of knowing 

 ■whether the anatomical elements arise by scission or by genesis 

 belonged purely to the domain of science, and were dependent 

 solely on observation and experiment. This however is by no 

 means the case. This is one of the subjects which have the 

 privilege of bringing into play passions by no means scientific. 

 In effect, the spontaneous genesis of the anatomical elements in 

 the blastemas seems to have a close connection with the theory 

 of spontaneous generation, which by some is so much execrated 

 and mocked. But if we contemplate the matter with composure 

 all this fury seems to have very little justification. Two facts 

 are very certain : the first, that anatomical elements multiply ; 

 the second, that they multiply by diverse processes, but in 

 general conditions which are identical. These principal facts 

 dominate all others. Little it matters whether a cell arises by 

 scission, by germination, by endogenesis, or by genesis. Defini- 

 tively the contents of an anatomical element do not differ 

 essentially from the environing blastema ; in both cases there are 

 organised substances, in the midst of which is effected the inces- 

 sant molecular movement which constitutes the fundamental 

 phenomenon of life. If assimilation prevails over disassimilation 

 there must necessarily result the formation of new living centres, 

 of new anatomical elements, and from the philosophical point 

 of view it matters little whether this new formation is effected 

 without or within a cell. 



Observation in effect shows that in the living tissues the 

 processes of scission and of genesis are sometimes associated, 

 and sometimes succeed each other. Nuclei, cells even, £ft:ising 

 from genesis, for instance leucocytes, can afterwards multiply by 

 segmentation and germination.' 



According to M. Kobin the advent of epithelial layers on the 

 surface of the cutaneous dermis and the mucous membranes 



^ Ch. Eobin, loc. cit., pp. 47, i&. 



