MUSCULAR CONTRACTILITY. 465 



a little of this agent under the skin, irritation, galvanic or 

 mechanical, applied to an exposed nerve, fails to produce 

 the slightest muscular contraction ; but if the stimulus be 

 applied directly to the muscles, they will contract vigorously. 

 In this way the nerves are, as it were, dissected out from the 

 muscles ; and the discovery of an agent that will paralyze 

 the nerves, without affecting the muscles, is conclusive proof 

 that the irritability of these two systems is entirely distinct. 

 A curious effect of the woorara, that we may note in passing, 

 is that in an animal under its influence, the muscular irrita- 

 bility is intensified, and persists much longer after death than 

 in animals not poisoned. 1 If a frog be poisoned with sulpho- 

 cyanide of potassium, precisely the contrary effect will be 

 observed ; that is, the muscles will become insensible to ex- 

 citation, while the nervous system is unaffected. This fact 

 may be demonstrated by applying a tight ligature around 

 the body in the lumbar region, involving all the parts except 

 the lumbar nerves. If the poison be now introduced beneath 

 the skin of the parts above the ligature, the anterior parts 

 only are affected, because the vascular communication with 

 the posterior extremities is cut off. If the exposed nerves be 

 now galvanized, the muscles of the legs are thrown into con- 

 traction, showing that the nervous irritability remains. Re- 

 flex movements in the posterior extremities may also be pro- 

 duced by irritation of the parts above the ligature. 2 



These experiments, most of which we have frequently re- 

 peated, taken in connection with the observations of Longet, 

 and the fact that isolated muscular fibres have been seen to 

 contract, leave no doubt of the existence of an inherent and 

 independent irritability in the muscular tissue. Contractions 

 of muscles, it is true, are normally excited through the ner- 

 vous system, and artificial stimulation of a motor or mixed 

 nerve is the most efficient method of producing the simul- 



1 BERNARD, Lemons sur Us e/ets des substances toxiyues et medicamentemes, 

 Paris, 1857, pp. 277, 320, 353, 



2 BERNARD, loc. oil., p. 354, et seq. 



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