228 JOSEPH DUERSON STOUT 



of the immediately underlying tissue, i.e., the most peripheral 

 portion of motor corona radiata, the following conclusions may 

 be drawn: 



19. The latency from the subcortical point is approximately 

 75 per cent of the latency of the overlying cortex. 



20. The amount of the current needed to excite the subcortical 

 point is not appreciably different with the apparatus used in 

 these experiments. 



21. The character of the reactions from the two regions is 

 practically identical. The stimulation of the subcortical point 

 usually reacts in activity of practically the same groups of 

 muscles as does stimulation of the cortical point. 



Motor reactions from stimulations of corpus callosum and of 

 corona radiata. The results from stimulation of the exposed 

 end of the corpus callosum may be summarized as follows : 



22. The corpus callosum is irritable to electrical stimulation 

 except at its posterior extremity. 



23. Stimulation of the anterior one-third results in move- 

 ments of the hind limb usually of the crossed side, but some- 

 times of the hind limb of the same side. 



24. Stimulation of the anterior half results in movements of 

 the fore limb of one or the other side, usually the crossed side. 



25. Stimulations of the anterior four-fifths result in movements 

 of the head and neck, of a bilateral nature. 



26. Stimulations applied to the middle two-fourths result in 

 changes of the respiratory activity, usually causing an increase 

 in the intake. 



27. The amount of current needed for the stimulation of the 

 exposed tissue of the corpus callosum is practically the same as 

 for stimulation of the surface of the cortex. 



28. The movements produced are as functionally perfect as 

 are those produced by stimulation of the cortical surface and are 

 apt to involve several joints in the same manner as do the cortical 

 responses. 



The results from stimulation of the structure of the corona 

 radiata, exposed by removal of a long wedge-shaped strip of 

 the cortex, may be summarized by saying that (29) motor reac- 



