THE PHYLOGEXY OF THE SOUL. 167 



mechanism of the soul. If speculative philosophy 

 assimilated only the most important of these signi- 

 ficant results of empirical biology, it would have a 

 very different character from that it unfortunately 

 presents. As I have not space for an exhaustive 

 treatment of them here, I will confine myself to a 

 relation of the chief facts. 



Each of the higher animal species has a character- 

 istic psychic organ ; the central nervous system of 

 each has certain peculiarities of shape, position, and 

 composition. The medusae, among the radiating 

 cnidaria, have a ring of nervous matter at the border 

 of the fringe, generally provided with four or eight 

 ganglia. The mouth of the five-rayed cnidarion is 

 girt with a nerve-ring, from which proceed five 

 branches. The bi-symmetrical platodes and the 

 vermalia have a vertical brain, or acroganglion, 

 composed of two dorsal ganglia, lying above the 

 mouth; from these "upper ganglia" two branch 

 nerves proceed to the shin and the muscles. In some 

 of the vermalia and in the mollusca a pair of ventral 

 " lower ganglia " are added, which are connected with 

 the former by a ring round the gullet. This ring is 

 found also in the articulata ; but in these it is con- 

 tinued on the belly side of the long body as a ventral 

 medulla, a double fibre like a rope-ladder, which 

 expands into a double ganglion in each member. 

 The vertebrates have an entirely different formation 

 of the psychic organ ; they have always a spinal 

 medulla developed at the back of the body ; and from 

 an expansion of its fore part there arises subsequently 

 the characteristic vesicular brain. 1 



1 Cf. Natural History of Creation. 



