TRANSACTIOl?*S OP THE SECTIONS. 673 



l^e nerves of on6 leg had been divided and the lower pari, of the 

 limb rendered perfectly insensible and incapable of voluntary* 

 motion, (but without stripping off the skin,) while the nerves 

 of the other had been left entire. The state of the muscles of 

 both limbs was examined after some days. The results of these 

 experiments were not uniform ; but in several, where every at- 

 tention to accuracy seemed to have been paid, the irritability 

 of the muscles in the palsied limbs appeared to be restored as 

 perfectly as in the others-, contractions being excited in them, 

 in several instances, by the galvanism from four or even two; 

 plates, whereas they had formerly been irritated until they were' 

 no longer excitable by that from fourteen plates. 



That the muscles which thus recovered their irritability had 

 lost all nervous connexion with the brain or spinal cord was 

 proved, not only by their obvious insensibility, but by after- 

 wards cutting off the heads of the animals and forcing a probe 

 along the spinal canal, which excited forcible contractions in all 

 parts excepting the palsied limbs. ; - .' ."■.'! 



Dr. Alison's paper contained the details of severalof these 

 experiments ; and he stated in conclusion, that as a positive 

 result in such an inquiry must always outweigh a negative one, 

 (particularly where a source of fallacy attending the latter can 

 be pointed out,) these experiments appear fully to justify the as- 

 sertion of Dr. Wilson Philip, that a muscle of voluntary motion 

 may recover its irritability by rest, although all its nerves be 

 divided ; and that they afford, perhaps, more direct evidence 

 than any others in support of the doctrine of Haller, now gene- 

 rally admitted in this country, that the property of irritability 

 in muscles is independent of any influence or energy continually 

 flowing from the nervous system, although, like every other 

 endowment of living animals, it is subjected to the control of 

 causes which act primarily on that part of the living frame. 



Dr. Allen Thomson expressed a doubt whether these expe- 

 riments warranted the conclusion drawn from them, not because 

 he acquiesced in the theory to which they are opposed, nor be- 

 cause he called in question the accuracy of the results described 

 to have been obtained, but because he knew that former experi-.- 

 menters had failed in producing such diminution or exhaustion! 

 of the irritability of muscles as had been found by Dr. Reid j^l 

 and conceived it possible that some of the numerous fallacies to 

 which such experiments are liable might not have been suf- 

 ficiently guarded against.* 



* A Committee, of which Dr. Thomson was a member, was appointed for the ' 

 repetition of the experiments, which has performed the duty assigned to it. 

 1834. 2x 



