LIFE AND MIND 



nevertheless very slight. To produce notice- 

 able obscuration the opaque object must ap- 

 proach very near ; and hence " we may infer 

 that nascent vision extends to those objects alone 

 which are just about to touch the organism, . . . 

 so that it amounts at first to Httle more than 

 anticipatory touch." ^ As we pass to higher 

 forms, we find the eye gradually increasing in 

 translucence, acquiring a convexity of surface, 

 liquefying internally into refracting humours, 

 while the nerve vesicles within multiply and 

 arrange themselves as retinal rods ; the result 

 being seen in the gradually increasing power 

 of the organism to adapt its actions to actions 

 occurring at a distance. The process and the 

 result of development are essentially the same 

 in the case of hearing and smell, though there 

 are great differences in the degrees to which 

 these senses are developed in the highest ani- 

 mals. 



Further extension of the correspondence is 

 effected, in the higher vertebrates, by the in- 

 crease in size and complexity of the cerebrum 

 and cerebellum. These pedunculated groups 

 of ganglia, which issue from the medulla, and 

 whose function it is to compound in higher 

 and higher aggregates the already compound 

 impressions received by the medulla, are capa- 



^ Spencer, Principles of Psychology y vol. i. pp. 314, 315. 

 [Part III. chapter iv. § 142.] 



