612 FOURTH REPORT — 1834. 



nervous system, supplies of a certain influence or energy, which 

 enables them to contract ; and that some of the statements of 

 Dr. Wilson Philip, in particular, are generally regarded as de- 

 cisive against this theorj\ 



Dr. Wilson Philip found by experiment, that the irritability 

 of a muscle of which the nerves were entire, was exhausted by 

 applying a stimulus directly to the muscular fibres (sprinkling 

 salt on them) even more quickly than that of a muscle of which 

 the nerves had been cut, and where all communication with the 

 supposed source of nervous influence or energy had been cut 

 off; and he states generally that a muscle of voluntary motion, 

 if exhausted by stimulation, will recover its irritability by rest, 

 although all its nerves have been divided. 



But in opposition to this statement, and in support of the old 

 theory of nervous influence continually flowing through certain 

 of the nerves into the muscles, it has lately been stated by 

 Mr. J. W. Earle, that when the nerves of the limb of a frog 

 were cut, the skin stripped off^, and the muscles irritated by 

 sprinkling salt on their fibres, until they had lost their power 

 of contraction, although they did not lose their power much 

 more quickly than when the nerves were entire, yet they did 

 not regain their poiver, although left undisturbed for five weeks ; 

 while the muscles of the limbs of another frog, similarly treated, 

 but of which the nerves were left entire, completely recovered 

 their irritability. 



It occurred as a fundamental objection to the experiment of 

 Mr. Earle, that in the case where the nerves had been divided, 

 the muscles had become inflamed ; being found at the end of 

 the five weeks " softer in their texture than natural, a good 

 deal injected with blood, and with some interstitial deposition 

 of fluid in them ;" while in the limb to which the salt had been 

 applied, but of which the nerves were left entire, and where the 

 irritability was recovered, " although the colour of the muscles 

 was rather darker than natural, their texture remained unchanged, 

 and there was no interstitial deposition of fluid in them." 



In these circumstances it might evidently be supposed that it 

 was the inflammation and disorganization of the muscles, not 

 the section of the nerves, which prevented the recovery of the 

 irritability in the case where the nerves had been cut; and it 

 became important to have the experiment repeated, with care to 

 avoid such injury of the limb of the animal as should cause 

 inflammation to succeed the section of the nerves. 



With this view. Dr. Reid performed a number of experiments 

 on frogs, in which the irritability of the muscles of both hind- 

 legs was exhausted or greatly diminished by galvanism, after 



