Car us, The Seat of Consciousness. 



185 



nert's diagram of the nervous system of man will teach you 

 that the voluntary motions are performed by different nerves 

 than the involuntary motions. CC in the diagram is the cortex, 

 or the gray substance of the hemispheres. Zand vS are the 

 lenticular body and the caudate body which both together form 

 the striate body. T is the thalamus, or so-called optic couch, 

 the great internodium of the central brain, the main func- 

 tion of which, as is well known, is, in spite of its name, not its 

 connection with the optic nerve ; V, the corpora quadrigemina 

 or Four Hills. The voluntary motions marked i. i. pass 

 through L or S, that is, either part of the striate body, the 

 lenticular, or the caudate body, to the anterior roots whence 



fet»t-Hf 



Fig. 2. (After Edinger). 



the motor nerves proceed to their various muscles. The in- 

 voluntary motions pass by 2. 2. through the thalamus. While 

 the voluntary motions cross from the right to the left, and vice 

 versa, the involuntary motions remain on the same side of the 

 body. The fact that the structures of the hemispheres may 

 perform their work in complete unconsciousness and that the 

 tracts of voluntary motions pass through the striate body nat- 

 urally suggests that the striate body is that organ in which the 

 element of consciousness is superadded. 



What is the nature of the striate body ? 



The striate body consists of two great ganglions, the lenticu- 

 lar body and the caudate body separated by the capsnla interna, 



