12 ROYAL SOCIETY OF CANADA 



con.sidoring- how young the animal is ; and such a case contrasts strongl}- 

 with the rapid exhaustion in the young dog. 



It is noteworthy that movements of the hind-leg can be induced 

 t>idy at'tei' removal of the cortex. 



Case HI. seems to be better pronounced still as an t'xaini)le of ver}" 

 <îarly cortical development — in fact, of localization. In this case also the 

 medulla seems to be in advance of the coi-tex. 



Case lA^. points to the presence of an indistinctly defined motor area 

 for the fore-limb. 



Case V. is in favour of primary development of the centre for the 

 fore-limb. 



Case VI. is one of a class not very readily explained, and will be 

 discussed latei-. 



Case VII. is especiall}' valuable, as it points clearly not onl}' to local- 

 ization but to the better development of the centre for the foredimb at 

 this age. This case also seems to be distinctl}' in favour of an earlier 

 functional development of the white matter of the brain. 



Case VIII. is an example of faii'ly definite localization of motor areas 

 for both limbs. 



Case IX. and Case III. illustrate the great ditt'erence in individuals. 

 Case III. is one of very early and Case IX. of a somewhat delayed cortical 

 development. 



In Case X. we get an illustration of the great différence in results 

 according to the strength of current used. 



Itomoval of the motor area, as in the case of the piii)i)ies, did not 

 give rise to ])aralysis. 



Case XI. illustrates the earlier develo})mi'nt of the centre for the 

 fore-limbs and also of the medulla. 



Case XII. shows that in a very short time there nui}' Ije a distinct 

 advance in the development of a centre. 



Case Xlir. points to distinct localization and to the more advanced 

 development of the centre for the fore-limb. 



Case XIV. is an example of the same features as Case XIII. 



Co.vcLusroNs. — The Dog ano the Cat Co.mi'Aked. 



.\t birth and for several days after the cortex does not respond to 

 electrical stimulation ; but in the cat the cortex usually responds at an 

 earlier date than in the dog. and is functionally active in some cases 

 before the eyes open. 



The centre for the tore-limb is responsive earlier than that for the 

 hind-limb. ^ 



Head movements, as in the case of the dog, can In' induced only at a 

 later date than movements of the limbs. 



