222 JOSEPH DUERSON STOUT 



tained from the stimulation of the corona radiata. In table 8 

 it is seen that the results from the stimulation of the corpus 

 callosum are fairly constant in the different animals, although 

 the extents of the area for the various types of muscular activity 

 differ slightly from animal to animal. For example, movements 

 of the hind limb resulted from stimulation of the anterior third 

 of the corpus callosum in cats 21 and 32, and from the anterior 

 half in cat 26. Movements of the fore limb resulted from the 

 stimulation of the anterior third in cat 21, from the anterior 

 half in cats 26 and 27, from the anterior two-thirds in cat 32, and 

 from the middle third in cat 18. 



The area most responsive to stimulation was the anterior 

 half, although in cats 18, 26, and 32 reactions were obtained from 

 all the structure, excepting the posterior fifth. The richness of 

 reaction from stimulation of the anterior portion is to be ac- 

 counted for by its nearness to the motor area and the consequent 

 richer supply of fibers passing presumably between the motor 

 areas of the two sides. It is to be noted that the most of the 

 movements produced by stimulation of the corpus callosum were 

 of the muscles of the right side of the body, while the left end 

 of the corpus callosum was exposed. The explanation of this is 

 not clear, but it is probably due to the fact that the fibers pro- 

 ducing the reactions are not members of the usual motor efferent 

 system, but are normally used to convey impulses from the left 

 cortex to associated motor mechanisms of the right cortex. 

 It is as yet impossible to say what their actual course is. Further 

 study of the motor cerebral control of the cat is necessary to 

 explain this matter. 



The area of the exposed tissue of the corona radiata yielding 

 the most satisfactory results was that portion of the structure 

 underlying the motor cortex and extending posteriorly close to 

 the anterior half of the corpus callosum. This is probably due 

 to the passage of the previously mentioned motor associational 

 fibers from the motor cortex to the corpus callosum, and thence 

 to the other hemisphere. The actual forms of movement pro- 

 duced from the stimulation of the corona radiata were in many 

 cases similar to the activity produced by stimulation of the 



