456 POPULAR SCIENCE MONTHLY 



mankind, do not remain the property of the philosophers. They ooze 

 out into general literature and become, so to speak, the common prop- 

 erty of mankind. In the present instance, we find in the attitude of 

 the majority of the cultivated persons who surround us to-day unmis- 

 takable traces both of the crude materialism which seems so natural 

 to man when he first begins to think about the mind, and of the line 

 of speculation indicated above. Men think of the mind as somehow 

 in the body, in the brain; and yet they are not willing to admit that 

 it is unequivocally in the body — in it as brain cells are, as blood cor- 

 puscles are, as are any of the material constituents of the body itself. 



Ask the average undergraduate student — who can not be accused 

 of having done much thinking for himself, but who holds the vague 

 opinions that he has absorbed from those about him — ask him where 

 his mind is, and he will probably answer that it is in his brain. Ask 

 him, further, whether there is any hope of getting at it as one may 

 hope to get at the material constituents of the brain, and I think he 

 will say, No ! It is there, and yet not exactly there; it is there in a 

 Pickwickian sense. He feels as Dr. Leidy did, and his feeling has 

 exactly the same foundation. It rests upon an ancient tradition. 



What, then, is the relation of mind and brain? We seem to be 

 left with an 'in' on our hands that is not really an in at all, but is 

 something else. What is it? Our student can not tell us, nor can 

 those from whom he has picked up his vague and inconsistent notions. 



To those who wish to think clearly all this is naturally unsatisfac- 

 tory. Those who busy themselves with the problem "are impelled to 

 try to make the matter less vague. Now and then, even in our time, 

 men go back, to accomplish this end, to something very like the ancient 

 materialism which the world outgrew so long ago. 



Thus we now and then hear it maintained that thought is a secre- 

 tion of the brain. Half a century ago much was said about this, and 

 to many the doctrine seemed plausible. It certainly does appear to 

 make clearer the relation of mind and body, if we hold that mental 

 phenomena are related to the brain as the saliva is related to the sali- 

 vary gland. If we can say this, we may maintain that the mind is in 

 the body in a literal and unambiguous sense of the word. 



But may we legitimately speak thus? The secretion of a gland is 

 a something so unequivocally material that it can be treated just like 

 other material things. It can be collected into a test-tube and ana- 

 lyzed by the chemist. Has any one ever succeeded in filling a test- 

 tube with mental phenomena? in bottling and analyzing in a labora- 

 tory pains and pleasures, memories and anticipations ? Dr. Leidy, who 

 knew a vast amount about the secretions of glands, did not confound 

 ideas with secretions, and would not even attempt to treat them in the 

 same way. 



