BY DR. MICHAEL FOSTER. 419 



sors, and the roof removed. Without waiting to stop the 

 bleeding, draw the cerebral hemispheres gently forward, and 

 carry a traverse incision from side to side with a blunt- 

 pointed bistoury through the brain in front of the corpora 

 bigemina, and with a narrow spatula remove the hemispheres 

 en manse from behind forwards. Place the animal on a perch, 

 and leave it to itself. Do not attempt to plug or staunch the 

 bleeding; a clot will soon form and serve as the best protec- 

 tion against further bleeding. Postpone putting sutures into 

 the flaps of skin until the bleeding has wholly ceased. 



If it be desired to keep the animal alive for any length of 

 time, it will be as well to allow it to remain perfectl}' quiet for 

 some time after the operation, avoiding all observations and 

 experiments upon it. Only on the second or third day begin 

 to feed it gradually with a few grains of softened barley or 

 of rice. 



Otherwise, observations may be begun as soon as the bleed- 

 ing has ceased. 



The bird so deprived of its cerebral hemispheres (together 

 with its corpora striata and optic thalami), if placed on the 

 finger or on a perch, will settle itself in a balanced position, 

 and remain thus for an indefinite period motionless, or all but 

 motionless, except as far as the breathing is concerned. It 

 seems to be plunged in the most profound sleep, with the head 

 drooping and the e3*elids closed. 



If irritated, it appears to awake; it opens its eyes, raises its 

 head, and more or less opens its wings, and otherwise moves 

 its body or limbs. 



If, while in a state of complete rest, perched on the fore- 

 finger, the finger be gently revolved, so as to throw the centre 

 of gravity outside the finger, the wingc will immediately spread 

 out as if for the act of flight. 



If thrown into the air, it will actually fly for some little dis- 

 tance, eventually settling down into its lethargic but balanced 

 condition. If in its flight it meets any objects it blindly strikes 

 against them. 



For a detailed description of the phenomena exhibited by 

 such a bird, see Flourcns's Systeme Nerveux, p. 123. 



O/-s. VII. Removal of the Cerebral Hemispheres in the Mam- 

 mal. A young rabbit, about two months old, is the most suit- 

 able animal to operate upon. It should be fed for some days 

 previously on dry food. The method of operating is very 

 much the same as in the bird. Fasten the animal on a Cer- 

 mak's rabbit-holder (Fig. 204), which should be raised at an 

 angle of 60 or so, in order that the head may be as high as 

 possible, and, consequently, the bleeding diminished. The 

 removal of the roof of the skull will be facilitated by first 

 making a small hole in each parietal with a trephine about a 



