HEMISPHERES. 421 



perfect health, with the wounds healed, and with the mental and 

 bodily functions entirely unimpaired, except that sight was perma- 

 nently lost in the eye of the injured side. 



The hemispheres, furthermore, are not the seat of sensation or of 

 volition, nor are they immediately essential to the continuance of 

 life. In quadrupeds, the complete removal of the hemispheres is 

 attended with so much hemorrhage that the operation is generally 

 fatal from this cause within a few minutes. In birds, however, it 

 may be performed without any immediate danger to life. Longet 

 has removed the hemispheres in pigeons and fowls, and has kept 

 these animals afterward for several days, with most of the organic 

 functions unimpaired. We have frequently performed the same 

 experiment upon pigeons, with a similar favorable result. 



The effect of this mutilation is simply to plunge the animal into 

 a state of profound stupor, in which he is almost entirely inatten- 

 tive to surrounding objects. The bird remains sitting motionless 

 upon his perch, or standing upon the ground, with the eyes closed, 

 and the head sunk between the shoulders. (Fig. 138.) The plu- 



Fig. 138. 



PIGEON, AFTER REMOVAL OF THE HEMISPHERES. 



mage is smooth and glossy, but is uniformly expanded, by a kind 

 of erection of the feathers, so that the body appears somewhat 

 puffed out, and larger than natural. Occasionally the bird opens 

 his eyes with a vacant stare, stretches his neck, perhaps shakes his 

 bill once or twice, or smooths down the feathers upon his shoulders, 

 and then relapses into his former apathetic condition. This state 

 of immobility, however, is not accompanied by the loss of sight, of 



