464 MOVEMENTS. 



in the muscles have led to the view that muscular contrac- 

 tility is dependent upon nervous influence, and consequently 

 that the muscles have no irritability or contractility, as a 

 property inherent in their own substance. This doctrine, 

 however, cannot be sustained. Bowman, in the course of his 

 researches into the structure and movements of voluntary 

 muscles, speaks of seeing the individual fibres contract after 

 they had been isolated and removed from all connection with 

 the nervous system ; and this has been frequently observed. 1 



The experiments of Longet, published in 1841, presented 

 almost conclusive proof of the independence of muscular 

 irritability. He resected the facial nerve, and found that it 

 ceased to respond to mechanical and galvanic stimulus, or, 

 in other words, lost its irritability, after the fourth day. Op- 

 erating, however, upon the muscles supplied exclusively with 

 filaments from this nerve, he found that they responded 

 promptly to mechanical and galvanic irritation, and con- 

 tinued to contract, under stimulation, for more than twelve 

 weeks. 8 In some further experiments it was shown that 

 while the contractility of the muscles could be seriously in- 

 fluenced through the nervous system, this was effected only 

 by modifications in their nutrition. "When the mixed nerves 

 were divided, the nutrition of the muscles was generally dis- 

 turbed ; and although muscular irritability persisted for some 

 time after the nervous irritability had disappeared, it be- 

 came very much diminished at the end of six weeks. 



These experiments are very striking and satisfactory ; but 

 the whole question was definitively settled by the observations 

 of Bernard on the peculiar influence of the woorara poison 

 and the sulphocyanide of potassium. As the result of these 

 experiments, it was ascertained that some varieties of woorara 

 destroy the irritability of the motor nerves, leaving the sen- 

 sitive filaments intact. If a frog be poisoned by introducing 



1 BOWMAN, The Minute Structure and Movements of Voluntary Muscle. 

 Philosophical Transactions, London, 1840, p. 488, et seq. 



2 LONGET, Traite de physiologic, Paris, 1869, tome ii., p. 606. 



