MODERN EVOLUTION. 



231 



the energy of the stimuli of light, sound, and so forth, 

 and the energy of the sensations which they arouse 

 in the nerve-channels." An excellent summary, with 

 references to the newest authorities on the subject, 

 is given by Prince Kropotkin in the Nineteenth 

 Century of August, 1896. 



All this, to the superficial onlooker, seems rank 

 materialism. But we cannot think without a brain 

 any more than we can see without eyes, and any 

 inquiry into the operation of the organ of thought 

 must run on the same lines as inquiry into the 

 operations of any other organ of the body. And 

 the inquiry leaves us at the point whence we began 

 in so far as any light is thrown on the connection 

 between the molecular vibrations in nerve-tissue and 

 the mental processes of which they are the indis- 

 pensable accompaniment. Changes take place in 

 some of the thousands of millions of brain-cells in 

 every thought that we think, and in every emotion 

 that we feel, but the nexus remains an impenetrable 

 mystery. Nevertheless, if we may not say that the 

 brain secretes thought as we say that the liver se- 

 cretes bile, we may also not say that the mind is 

 detachable from the nervous system, and that it is 

 an entity independent of it. Were it this, not only 

 would it stand outside the ordinary conditions of 

 development, but it would also maintain the equi- 

 librium which a dose of narcotics or of alcohol, or 

 which starvation and gorging alike rapidly upset. 



In his posthumous essay On the Immortality of 



