THE FUNCTIONS OF THE NERVOUS SYSTEM. 
269 
whose function is supported by stimuli peculiar to themselves, being still 
supplied with nerves, of the use of which Haller gave no satisfactory account. 
It appeared to me that the question could only be determined by some expe- 
riment capable of directly ascertaining whether the excitability of muscles 
is maintained by the influence they receive from the nerves, or impaired as by 
other stimuli. On trial, the latter was found to be the case. Muscles whose 
nerves had been divided, sustained the action of the same stimulus longer than 
those whose nerves were entire, and which consequently were exposed to the 
action both of the nervous power applied by the will of the animal and the 
artificial stimulus*. The power of the muscle, therefore, is independent of 
the nervous power, and is affected by it in the same way as by other stimuli. 
The experiments by which all the other functions just mentioned, with the 
exception of the maintenance of animal temperature, have been ascertained to 
be functions of the nervous power, I have laid before the Society, which has 
done me the honour to publish them. From these experiments it appeared 
that the functions in question were always destroyed by depriving their 
organs of the influence of the nervous system. That the maintenance of 
animal temperature is a function of the nervous system, properly so called, 
appears from a variety of facts generally known, the temperature either of a 
part or of the whole body being lessened by any cause that impairs the action 
of particular nerves in the former instance, or of the whole nervous system in 
the latter. The question then is, is the nervous system capable of all these 
functions after the sensorial power is withdrawn ? 
At the moment of what we call death, the sensorial functions cease, the 
animal no longer feels or wills. Whether the nervous functions properly so 
called still continue, can only be determined by experiment. That the nerves 
when stimulated are still capable of exciting the muscles of voluntary motion 
is a fact generally admitted ; and that they are still capable of exciting the 
action of the muscles of involuntary motion, appears from many experiments 
related in the second paper, which I had the honour to present to the Society, 
and which was published in the Philosophical Transactions of 1815. That 
the nervous system is capable of causing the evolution of caloric, which 
supports animal temperature after the sensorial power is withdrawn, appears 
* My Treatise on the Vital Functions, third edition, Exper. 34, 35. 
