— 
FUNCTIONS OF SPINAL CORD :—REFLEX ACTION. 376 
“the edge of the eyelid be touched with a straw, the lid imme- 
‘diately closes ; if a candle be brought near the eye, the pupil 
contracts (§ 534); if liquid be poured into the mouth, it is 
swallowed ; if @ foot be pinched or be burnt with a lighted 
taper, it is ‘withdrawn ; and, if the experiment be made upon 
Fa Frog, the animal will leap away as if to escape from the 
source of irritation. The respiratory movements, too, are kept 
up with regularity; so that there is no impediment to the 
continuance of the circulation, and the organic life of the 
animal may thus endure for some time. In one of the experi- 
ments made with the view of ascertaining the degree in which 
the activity of the Cerebrum is essential to the maintenance 
of life, a pigeon was kept alive (if alive it could be called) for 
‘some months after the removal of its cerebrum,—running 
when it was pushed, fiying when it was thrown into the air, 
Sein drinking when its beak was plunged in water, swallowing 
which was put in its mouth,—though at all other times, 
ben left to itself, appearing like an animal in prokuia 
t 466. It is evident, therefore, that we are not to ae the 
| Brain (according to the former opinion of Physiologists, and 
‘the belief which is still commonly entertained) as the only 
tre of nervous power, and as essential to the maintenance 
of the life of the body; and that we must attribute to the 
Spinal Cord no small amount of independent power. We 
t be disposed to infer, from the statements in the last 
ph, that an animal whose brain has been removed can 
still feel and judge and perform voluntary motions by means 
of the Spinal Cord; but this, again, would be putting a wrong 
interpretation upon the phenomena in question. It is ob- 
Served that the motions performed by an animal in such 
circumstances are never spontaneous ; they are always excited 
by a stimulus of some kind. Thus a decapitated Frog, after 
the first violent convulsive movements occasioned by the ope- 
ration have passed away, remains at rest until it is touched ; 
and then its leg, or even its whole body, will be thrown into 
Sudden action, which immediately subsides again. In the 
lame manner, the action of swallowing is not performed, 
xcept when it is excited by the contact of food or liquid 
$ 195); and even the respiratory movements, spontaneous as 
hey seem to be, would not continue long, unless they were 
