V ANIMAL AUTOMATISM 213 



only, or at least the chief, function of the soul ; but it is because 

 the mechanism of our body is so disposed, that the motion of 

 the hand towards our eyes excites another movement in our 

 brain, and this sends the animal spirits into those muscles 

 which cause the eyelids to close." 



Since Descartes' time, experiment has eminently 

 enlarged our knowledge of the details of reflex 

 action. The discovery of Bell has enabled us to 

 follow the tracks of the sensory and motor impulses, 

 along distinct bundles of nerve fibres ; and the 

 spinal cord, apart from the brain, has been proved 

 to be a great centre of reflex action; but the 

 fundamental conception remains as Descartes left 

 it, and it is one of the pillars of nerve physiology 

 at the present day. 



V. The motion of any given portion of the matter 

 of the brain excited by the motion of a 

 sensory nerve, leaves behind a readiness to 

 be moved in the same way, in that part. 

 Anything which resuscitates the motion 

 gives rise to the appropriate feeling. This 

 is the physical mechanism of memory. 



Descartes imagined that the pineal body (a 

 curious appendage to the upper side of the brain, 

 the function of which, if it have any, is wholly 

 unknown) : was the instrument through which the 

 soul received impressions from, and communicated 

 them to, the brain. And he thus endeavours to 

 1 See above : p. 189, iwte. 



