[mills] FU^■CTrONAL DEVELOPMENT OF CEREBRAL COKTKX 18- 



The white mtitter lying beneath the cortex is iisuall}^ resj)onsive earliei 

 than the cortex, and this has been more clearly marked in the case of the cat . 



The functional activity of the brain of the very young cat pei-sists 

 longer under the ordinary conditions of experiment than in the do". 



The same remarks as to distinct advance in a very short period, and ne«-- 

 ative results of ablation of the cortex, hold foi- the cat equally with the do»-. 



Upon the whole the motor centres in the cat are developed .somewhat 

 earlier than in the dog. 



E X P E R I M E In T A J . II E S V L T S . 



III. — The Rabbit. 



Case I.— Belgian, Hare rabbit ; 7th or Sth day. — Eyes unopened. Ether. 



The most that can be said is th-^it with a very strong current (D), there is 

 the suspicion of incipient movement of the fore-leg. 

 Case ll.~ Belgian Hare rabbit of same litter ; 10th fZa?/.— Ether. 



With a very strong current no distinct localized movement. The medulla 

 seems to be somewhat more responsive than the cortex, but no very definite 

 statements can be made. 



Case III.— Belgian Hare rabbit of satne litter ; 13th day.— Eyca open. Ether. 



With current B, get movement of fore-leg and mouth parts ; on increasing 

 the strength of current, grinding of the teeth is produced. On the opposite 

 side, get fore-leg and head movemeiit (to opposite side). These movements are 

 all distinct and follow on stimulation of différent parts of the cortex— a clear 

 case of localization. Similar results follow on stimulating the medulla. In 

 neither case are there movements of the hind-leg. 



Case IV.— Rabbit ; luth f?o^.— Ether. 



No movement with any strength of current. Cortex removed over a lai-ge 

 area. With current B, get movement of the fore leg and head to opposite side, 

 but with no s-ery clear localization. 



Case V.— Rabbit ; 12th day.— Eyes open. Ether. 



Both sides of the brain exposed with but little loss of blood. Strong cur 

 rent (C), used on both sides of the brain with negative results .so far as the 

 limbs are concerned, but with slight turning of the head to tlie opposite side 

 on stimulating each side of the brain. 



On renmval of the cortex and stimulating with the .same strength of cur- 

 rent, the same result follows, and, in addition, chewing movements. 

 Ca.se VI.— Rabbit ; loth day.—FAhev. 



With current B, only movement that of head to opposite side ; with some- 

 what stronger current, get. in addition, chewing movements and movement of 

 the fore-leg. The cortex is now excised. The movements are more marked, 

 especially as regards the fore-limb. Xo movement of the hind-limbs under 

 any circumstances. 



EXPEEniEXTAL RESULTS. 

 IV. — The Caw (Guinea-pig). 



As is well known, the cavy is born in an advnnced condition of de- 

 velopment. In a few hours it can run about, eat, etc. Its eyes are open 

 at birth, and it sees and hears well ; if not then, at least in a few hours. 



