CHAPTEE IV. 



OF ANIMAL GENEEATION. 



The two living kingdoms were probably identical originally, as 

 tbe naturalists, partisans of evolution, try to demonstrate by 

 patient researcbes and ingenious pictures of affinity. Assuredly 

 tbere still exist many points of union between the two grand 

 divisions of tbe organic world, and tbere is no differential 

 characteristic constant and applicable to all animal and vegetal 

 species. We must therefore expect to meet with a great anal- 

 ogy between the principal phenomena and even the grand 

 processes of reproduction in the two kingdoms. 



At the lowest degrees of the animal hierarchy, in the beings 

 little or not at all differentiated, for example in the polypi, the 

 morphological centre of the whole creature seems to exist, in 

 each of the cells, and any portion whatsoever of the body can 

 reproduce the whole animal. It is in the species thus endowed 

 with an enormous power of reparation, of regeneration, that 

 fissiparous reproduction is especially observable. The individual, 

 on attainiag his maximum of growth, overflows, so to speak, 

 beyond his natural limits ; he unfolds himself, and foi'ms, by 

 simple division, a new individual (Fig. 46). This process of 

 multiplication acquires sometimes an extreme energy, if it is 

 true, as M. Balbiani affirms, that in forty-two days a paramecium 

 canprodace, by fissiparity, 1,384,116 new individuals, that is to 

 say, that a single animal, O^^jQ long grows 277 metres -in bulk. 

 "We see then the body of the infusorium lengthen, thereupon 



