DISCOURSE ON METHOD. 59 



and less agitated parts must necessarily be driven 

 aside from that point by the stronger which alone in 

 this way reach it. 



I had expounded all these matters with sufficient 

 minuteness in the Treatise which I formerly thought 

 of publishing. And after these, I had shewn .what 

 must be the fabric of the nerves and muscles of the 

 human body to give the animal spirits contained in 

 it the power to move the members, as when we see 

 heads shortly after they have been struck off still 

 move and bite the earth, although no longer ani- 

 mated; what changes must take place in the brain 

 to produce waking, sleep, and dreams, how light, 

 sounds, odours, tastes, heat, and all the other quali- 

 ties of external objects impress it with different 

 ideas by means of the senses ; how hunger, thirst, 

 and the other internal affections can likewise 

 impress upon it divers ideas ; what must be under- 

 stood by the common sense (sensus communis) in 

 which these ideas are received, by the memory 

 which retains them, by the fantasy which can 

 change them in various ways, and out of them com- 

 pose new ideas, and which, by the same means, dis- 

 tributing the animal spirits through the muscles, 

 can cause the members of such a body to move in as 

 many different ways, and in a manner as suited, 

 whether to the objects that are presented to its 

 senses or to its internal affections, as can take place 

 in our own case apart from the guidance of the will. 

 Nor will this appear at all strange to those who are 

 acquainted with the variety of movements per- 

 formed by the different automata, or moving 



