LECT. XIV. XV. CONCLUSIONS. 265 



stimulant, applied to the spinal marrow, or the lumbar 

 plexuses, being substituted. 



Lastly, I have repeated these experiments by placing 

 very fine layers of different substances between the nerve 

 of the galvanoscopic frog and the muscular surface where 

 the induced contraction is developed. A leaf of gold, or a 

 very thin and insulating lamina of mica, or glazed paper, 

 being interposed, prevents the production of the phenome- 

 non ; that is to say, the contractions by induction do not 

 occur in the galvanoscopic frog; but, on the contrary, a leaf 

 of fine paper, moistened with water, does not prevent the 

 occurrence of this contraction. 



Conclusions. From the whole of these facts we are 

 authorized to conclude, 



1st. That we cannot consider the induced contractions 

 of the galvanoscopic frog, to be due to the electric current. 



2d. And that we might, on the contrary, assume, that an 

 electric discharge happens during the contraction of the 

 muscle. 



I have tried a great number of experiments with the view 

 of supporting, by facts, this explanation of induced contrac- 

 tions. With this aim, I formed a pile of entire frogs, and 

 closed the circuit with the two extremities of the galvano- 

 meter. When the needle had become stationary, I touched 

 the nerve of the frogs, with a solution of potash, in order 

 to excite contractions. By operating in this manner I have 

 often seen the deviation of the needle increase several de- 

 grees, and afterwards return to 0. When the frogs had 

 been touched several times with potash, or were so weak- 

 ened that, on submitting them again to the stimulating ac- 

 tion of the alkali, no more contractions ensued, it usually 

 happened that no further deviation of the needle could be 

 obtained. 



Finally, by moistening the nerves of frogs arranged in a 



