The Senses of Animals. 301 



that happens. But if (in the frog) it be replaced on the 

 choroid layer from which it has been stripped, the visual 

 purple is reformed. The explosive is thus reconstructed 

 and the sensibility is restored. Thus, as fast as the 

 explosives are fired off by sense-stimuli, so fast in normal 

 life are they reconstituted and the sensibility restored. 

 Meanwhile the explosion at the end-organs has fired the 

 train of explosives in the nerve, and created molecular 

 explosive disturbances in the brain. Thence the explosive 

 waves pass down other nerves to muscles or glands, and, 

 giving rise therein to further explosions, take effect in the 

 activities of the organism. 



We shall have to consider these activities hereafter. 

 We must now turn to the psychical or mental accom- 

 paniments of the explosive disturbances in the brain or 

 other aggregated mass of nerve-cells. 



