210 ANIMAL AUTOMATISM. [LECT. 



IV. The motion of the matter of a sensory nerve 

 may be transmitted through the brain to 

 motor nerves, and thereby give rise to con- 

 traction of the muscles to which these motor 

 nerves are distributed; and this reflection 

 of motion from a sensory into a motor nerve 

 may take place without volition 9 or even con- 

 trary to it. 



In stating these important truths, Descartes 

 denned that which we now term "reflex action." 

 Indeed he almost uses the term itself, as he talks of 

 the "animal spirits" as "reflechis," 1 from the sensory 

 into the motor nerves. And that this use of the 

 word " reflected " was no mere accident, but that the 

 importance and appropriateness of the idea it suggests 

 was fully understood by Descartes' contemporaries, is 

 apparent from a passage in "Willis's well-known essay, 

 "De Anima Brutorum," published in 1672, in which, 

 in giving an account of Descartes' views, he speaks of 

 the animal spirits being diverted into motor channels, 

 " velut undulatione reflexa." 2 



Nothing can be clearer in statement, or in illus- 

 tration, than the view of reflex action which Descartes 

 gives in the " Passions de 1'Ame," Art. xiii. 



1 " Passions de 1'Ame," Art. xxxvi. 



2 " Quamcumque Bruti actionem, velut automati mechanic! motum 

 artificialem, in eo consistere quod se primo sensibile aliquod spiritus 

 animales afficiens, eosque introrsum convertens, sensionem excitat, a 

 qua mox iidem spiritus, velut undulatione reflexa* denuo retrorsum 

 commoti atque pro concinno ipsius fabricse organorum, et partium 

 ordine, in certos nervos musculosque determinati, respectivos membro- 

 rum motus perficiunt." WILLIS : "De Animsi Brutorum," p. 5, ed. 

 1763. 



