278 The Older Doetrines [lect. 



" with the spirits being excited, look back upon the object by 

 " whose impulse they are set in motion, and for the sake of 

 " laying hold of it, or of driving it away, very quickly delegate 

 " to other spirits flowing along the ducts of the nerves, and so 

 " on to other spirits of the members and of the motor parts, 

 " occupying their proper places, the orders to carry out the 

 " appropriate movements. Thus sense gives rise to imagination, 

 " this to memory or to impulse, or to both of them, and impulse 

 " finally gives rise to local movements, which bring about the 

 " performance or the avoidance of the apparent good and evil." 



Thus all sensory nerves carry their impulses (as we now 

 call them) to the corpora striata, which Willis repeatedly 

 speaks of as the sensorium commune, the common seat of 

 sensation, and produce further effects, first in the corpus 

 callosum and then in the cortex. The same path is taken 

 in the reverse direction by the motor impulses started by 

 affections of mind. These also pass by the corpora striata, 

 which Willis appears to have recognized as important organs 

 no less of movement than of sensation; and his medical 

 experience enabled him in many cases to connect disease in 

 them with the symptoms of paralysis. We may add in passing 

 that the same experience, as well as the results of his 

 anatomical researches, led him to suppose that the optic 

 thalamus was especially connected with sight. 



I must not however tarry longer on Willis and his views ; 

 yet I cannot refrain from quoting one more passage which on 

 the one hand shews that he had dimly laid hold of the modern 

 doctrine of reflex action (and indeed other passages shew this), 

 and on the other hand illustrates the difficulty which he met 

 with in explaining all the phenomena of brute beasts by the 

 mere possession of a material corporeal soul in the absence of 

 that rational soul which belonged to man alone. 



" We may admit that the impression of an object, driving 

 " the animal spirits inwards, and modifying them in a certain 

 " peculiar manner, gives rise to sensation, and that the same 

 " animal spirits in that they rebound from within outwards in a 

 " reflected wave as it were, call forth local movements. We have 

 " not, however, as yet stated how this soul or some part of it 



