350 ON oTixrst. 



Effects of fhexirural nerves hi such a manner, that they were entirely 



M?S™sy«em. ^'"^^ *^^ every other part, and obtained about eight or ten 

 lines of nerve totally clear and in some very large frogs eren 

 more. I then let fall the nerves of each thigh into a small 

 hollo-v glass, which received them in such a vray that I can 

 fill each glass with a fluid of any kind without its touching 

 the adjacent muscles. I usually have been able to put into 

 these glasses;, such a proportion of whatever I wish to try 

 on fhe nerves, as to cover the greater part of them with it, 

 without its being possible for any of the liquer to find its 

 way to the thighs and mix with the blood. In this way i 

 can make a comparison betwixt the nerves, that are en- 

 venomed and those that are not; compute the time they 

 continue to contract the muscles, and judge of the vivacity 

 of the motions." 



" At the end of the first ten m.inutes I stimulated the me- 

 dicated nerves, i. e. those, to which the solution of opium 

 was applied, and those which were not medicated, and found 

 that the two extremities, the right as well ag left, contracted 

 with the same force and vivacity." 



*' At the end of twenty minutes, I tried the stimulation, 

 and could perceive no sensible diilerence betwixt the motions 

 of (he two feet, which were almost as lively as those in the 

 ftrst experiment," 



" At the end of thirty minutes, the motions of the two 

 feet were feebler, but alike in both." 



''At the end of forty minutes, the feet scarcely con- 

 tracted, but their distinct muscles were clearly seen to con- 

 tract, ^vhen the crural nerves were stimulated, and the mo- 

 tions of these muscles were equally lively in each foot." 



" At the end of fifty minutes, the motions were rery 

 small ' fr«m compression of the nerves,' but alike in both 

 sides." 



" At the end of eighty minutes, there was no longer any 

 motion to be observed in several of the frogs, in whatever 

 ■way I stimulated either the crural nerves that were medicated, 

 or those which were not so." 



'^ I can ccinceive," adds Fontana, ^' nothing more deci- 

 sive and more certain tlian from this series of experiments, 

 that the action of opium is not directly on the nerves." 



2dly. 



J 



