ARE ANIMALS AUTOMATONS? 727 



in physiology but in pliilosojohy. Till his time it was the notion that 

 visible bodies, for example, gave from themselves a kind of film which 

 entered the eye and so went to the brain, S2yecies intellectuales as they 

 were called, and thus the mind received an actual copy or picture of 

 things which were given off from it. In laying down that ^proposition 

 upon what I imagine to be a perfectly irrefragable basis, Descartes laid 

 the foundation of that form of j^hilosophy which is termed idealism, 

 which was subsequently expanded to its uttermost by Berkeley, and 

 has taken all sorts of shapes since. 



But Descartes noticed not only that under certain conditions an 

 impulse made by the sensory organ may give rise to a sensation, but 

 that under certain other conditions it may give rise to motion, and 

 that this motion may be effected without sensation, and not only with- 

 out volition, but even contrary to it. I know in no modern treatise of 

 a more clear and j^recise statement than this of what we understand 

 by the automatic action of the brain. And what is very remarkable 

 is, that, in speaking of these movements which arise by a sensation 

 being as it were reflected from the central apparatus into a limb — as, for 

 example, when one's finger is pricked and the arm is suddenly drawn 

 up, the motion of the sensory nerve travels to the spine and is again 

 reflected down to the muscles of the arm — Descartes uses the very 

 phrase that, we at this present time employ. And. the last great ser- 

 vice to the physiology of the nervous system which I have to mention 

 as rendered by Descartes was this, that he first, so far as I know, 

 sketched out the physical theory of memory. What he tells you in 

 substance is this, that when a sensation takes place, the animal spirits 

 travel up the sensory nerve, pass to the appropriate part of the brain, 

 and there, as it were, find their way through the pores of the substance 

 of the brain. And he says that, when the particles of the brain have 

 themselves been shov^ed aside a little by the single passage of the 

 animal spirits, the passage is made easier in the same direction for 

 any subsequent flow of animal spirits, and that the repetition of this 

 action makes it easier still, until at length it becomes very easy for 

 the animal spirits to move these particular particles of the brain, 

 the motion of which gives rise to the appropriate sensation, until at 

 length the passage is so easy that almost any thing, especially an asso- 

 ciated flow which may be set going, allows the animal spirits to flow 

 into these already open pores more easily than they would flow in any 

 other direction ; and in this way a flow of the animal spirits recalls 

 the image — the impression made by a former sensory act. That, 

 again, is essentially in substance at one with all our present physical 

 theories of memory. In one respect Descartes proceeded further than 

 any of his contemporaries, and has been followed by very few of his 

 successors in later days. Descartes reasoned thus : " I can account for 

 many such actions, many reflex actions taking place without the inter- 

 vention of consciousness, and even in opposition to the will." So far 



