278 NERVOUS FORCE. LECT. XIV. XV. 



vanoscopic frog upon the muscles of the thigh, when the 

 latter suffers no contraction, induced contraction is also 

 wanting. 



When experimenting upon rabbits and dogs, I have 

 been able to operate with the electric current upon the 

 nervous filaments distributed to the kidneys, stomach, and 

 intestines ; the nerve of the galvanoscopic frog was, during 

 the experiment, stretched upon these different organs, and 

 in an analogous position to that which it had when it was 

 placed upon the muscles. I never obtained any sign of 

 induced contraction. 



I also sought to discover whether induced contraction 

 occurred when the nerve of the galvanoscopic frog was 

 placed on that which is irritated. For this purpose two 

 galvanoscopic frogs were prepared, and the nerve of the 

 first was placed upon that of the second, at points very 

 near to the leg. In order not to omit any precaution in 

 this experiment, we placed the two frogs upon turpentine, 

 and afterwards irritated, either with the current or with 

 some other stimulant, the upper parts of the nerve of the 

 frog, which I shall continue to call inducteous. The 

 galvanoscopic frog manifested no induced contractions ; 

 whilst, on the contrary, it showed them immediately, if its 

 nerve was disposed upon the gastrocnemius of the other 

 frog. It is needless to add, that in making use of the cur- 

 rent in order to excite the inducteous contraction, we must 

 never put the conductors of the pile in contact or in proxi- 

 mity with the nerve of the galvanoscopic frog. We may 

 conclude from this experiment, that an irritated nerve, and 

 within which the unknown principle which excites the con- 

 traction in the muscle and the sensation in the brain is cer- 

 tainly propagated, does not act upon the nerve of the 

 galvanoscopie frog placed in contact with it. 



I will also relate the following experiment : I exposed 



