TRANSACTIONS OF THE SECTIONS. 137 
The animal ran about in great uneasiness, just as it had done before its head was 
off. In vain I waited for it to rub itself against the side of the box ; it curled itself 
up, and seemed about to die. Some time afterwards I again touched it with the 
acid; it again became disorderly, and I then pushed it towards the side of the box ; 
but it did not move until [ pushed it slowly forwards so that its flank might come in 
contact with the wood; this succeeded: this seemed to supply the very remedy it 
wanted, for it continued crawling slowly and with intervals of rest, its body curved 
outwards so as to continue in contact with the wood, and its hind leg pressed close 
to the tail, and thus, as before, it rubbed away the acid. There are two points 
noticeable here :—first, the readiness with which a sensation of contact suggested a 
means of relief; secondly, that this was the only newt which, in my experiments, 
ever hit upon this plan, and this one did so as well without its head as with it. The 
repetition of the act precludes the idea of its being an accident. 
It is unnecessary to trespass on your time by citing the observations of numerous 
physiologists testifying to the spontaneity of decapitated animals—all remember 
such cases. I divided the chord of a newt between the fifth and sixth cervical 
vertebre. The convulsions which followed were almost as severe as those which 
follow decapitation. After a few minutes it tried to rise, but failed. Bubbles of 
carbonic acid were constantly expired. After fifteen minutes it turned completely 
round, and crawled five steps forward, dragging the hinder segment after it like a log, 
the hinder legs not moving at all. This was repeated several times. In fifteen 
minutes more sensibility was detected in the hinder segment. Here was a case which 
would have been pronounced very simple :—Division of the chord had seemingly 
destroyed all power of voluntary movement in the limbs below the section. The 
hind legs seemed paralysed. When the anterior segment was irritated, the animal 
crawled away dragging the posterior segment motionless after it. When this pos- 
terior segment was irritated, the animal did not crawl, but simply withdrew the limb 
or tail. If I touched the tail, or hinder leg, with acetic acid, the whole of the 
posterior segment (in which volition was said to be destroyed) began to move, and 
the legs set up the crawling action, attempting to push the whole body forward, 
which could not be effected, because the anterior segment was perfectly motionless. 
The hind legs, which never moved when the anterior segment was irritated, moved 
now in obedience to the spinal volition; and the anterior segment, which before 
seemed so energetic in its voluntary movements, was now perfectly unmoved. Each 
centre rules its own segment. If the cessation of motion of the hind legs, when the 
animal crawled, is a proof that voluntary power was destroyed in those legs, the cessa- 
tion of motion of the fore legs, when the hind legs moved, is equally a proof that 
voluntary power was destroyed in the fore legs. The real truth seems to be that each 
segment has its own volitional centre. [Pfliiger’s experiments, which the author had 
repeated and varied, were here detailed, in evidence of the choice manifested by de- 
capitated frogs.] I have at this moment a newt with the chord divided near the centre 
of the back. The operation was performed four days ago, and the animal has so far 
recovered from it that no spectator could distinguish between the voluntary power of 
its two segments. When the flame of a wax match is brought near the cerebral seg- 
ment, the fore legs set to work, and the animal crawls away, dragging the hinder 
segment along. When the flame is brought near the spinal segment, the hind legs 
set to work, and the body moves sideways, the anterior segment remaining perfectly 
quiescent. All other stimuli produce similar results. I venture to submit that the 
explanation proposed to meet this case, namely, that division of the chord produces 
two independent volitional centres, is far more consistent with the phenomena, than 
the explanation offered by the reflex theory : unless the actions of the posterior seg- 
ment of the newt are evidences of sensation and volition, I know of no kind of evi- 
dence for the existence of such properties in the cerebral segment. * * * * 
I will not occupy the attention of this Meeting with the recital of other experi- 
ments. Those already cited suffice to indicate the nature of the evidence on which 
I found my positions. And indeed I might rest on one simple fact as proof that the 
spinal chord is a sensational centre, namely, the fact that whenever sensibility is 
destroyed all actions cease to be co-ordinated. Every one knows how greatly our 
muscular sensibility aids us in the performance of actions; but it has apparently 
been forgotten, that if sensibility be destroyed in a limb, by section of the posterior 
