x] of the Nervous System. 271 



goes far to explain the influence which they had in their time, 

 they do not of themselves form any real solid contribution to 

 knowledge. They are indeed to a large extent the views of 

 Descartes, modified by more exact anatomical knowledge, oc- 

 casionally by sound physiological deductions, in which we may 

 probably trace the influence of Lower and other of Willis's 

 contemporaries, but chiefly and especially by certain conceptions 

 and certain modes of expression which appear to be entirely 

 Willis's own. 



He admits with Descartes that man possesses a rational 

 soul, an immortal, incorporeal soul, but that, putting aside 

 everything which is due to the direct activity of this rational 

 soul, the nervous as well as the other phenomena both of man 

 and of animals may be regarded as the phenomena of a 

 corporeal machine. While, however, Descartes makes it his 

 first object to prove that the body of man is, in this way, a 

 machine, and that all known physiological phenomena may be 

 adequately explained on this hypothesis, and has a secondary 

 interest in physiological problems as such, caring for them only 

 so long as they illustrate his thesis, Willis is especially con- 

 cerned with these same special problems and in no case dwells 

 on Descartes' main thesis. 



Descartes speaks only of the animal spirits, accepting off- 

 hand, as we have seen, the old views concerning them, but 

 treating them from an exact physical point of view. Willis, in 

 his rhetorical way, speaks of these animal spirits as constituting 

 part of a corporeal soul, to whose activity are due the nervous 

 phenomena of man and the higher animals ; and he is especially 

 concerned with the features and mode of action of this corporeal 

 soul, this soul of the mere machine. He puts forward the 

 view that this corporeal soul consists of two parts, one residing 

 in the blood, the other in the brain and nervous system ; and 

 he believed that he had made a great discovery in recognizing 

 the exact nature of these two parts of the soul. As I have said, 

 Willis's mind was of that sort which when it has hit on an 

 illustration or discovered an analogy, thinks it has found a proof. 

 And the great discovery was simply this, that the part of the 

 soul residing in the blood was of the nature of 'flame,' and 



