and Remarks on the Contractions of the Frog, 199 



vani, have made similar experiments ; they found, for instance, 

 that if the four nerves of one of the organs are severed, the 

 discharge immediately ceases in this organ, while it manifests 

 itself continually in the other ; and that if only two or three 

 nerves are cut, the sensation is limited to points corresponding 

 to the nerves which have remained intact: they concluded 

 from their observations that the brain and the nervous trunks 

 exercise an influence which determines the electrical faculty 

 of the torpedo. Matteucci has arrived at the same conclusions, 

 but he has determined better than any one had done before 

 him the extent of this influence, as will be seen. If we tie 

 the nerves, the same effects are produced as on cutting them. 

 When the nerves have been severed, if one of the nervous 

 trunks which branches in the organ is drawn forth with 

 pincers, we still obtain some discharges. If the brain is laid 

 open, and certain parts be irritated with any body whatsoever, 

 the discharge is instantly evident. The first lobes (the cerebral) 

 may be irritated, severed, and even destroyed without the dis- 

 charge disappearing; the same is the case with the third lobe. 

 As to the fourth, it may be touched without producing power- 

 ful discharges ; on destroying it, even when the others are 

 left whole, the electrical power of the animal is entirely de- 

 stroyed. This observation, which is very remarkable, will 

 certainly be of great interest to physiologists on account of its 

 singularity. 



When the animal is in such a state of torpidity as not to 

 give any more discharges, when the ordinary excitatives are 

 employed, if we then lay open the brain and touch the elec- 

 trical lobe, the discharges appear with force going indifferently 

 from the back to the belly, and from the belly to the back, 

 whilst no effect is produced on irritating the other parts of 

 the brain ; if we employ electricity as the excitative we obtain 

 a similar result. 



We think it our duty to mention in this place that M. 

 Flourens had already proved by direct experiments, published 

 in 1825, that the last lobe of the brain is in fish in general the 

 special encephalic organ of respiration. If one side of this 

 lobe is cut away, the movement of the operculum of this side 

 is immediately destroyed ; the movement of the operculum of 

 the opposite side continues. If the lobe be entirely taken away, 

 the play of the two opercula ceases suddenly. Flourens more- 

 over proved that the action of the last lobe (of the lobe situ- 

 ated behind the cerebellum of the brain) upon the opercula 

 continues complete after the taking away of all the other parts 

 of the encephalus, as after the taking away of the spinal mar- 

 row, whether these two removals (that of all the other parts of 



