Chemical Agents on the Nervous System. 261 



glasses of the " couronne de tasses," we placed them care- 

 fully in contact with discs of silvei- (bright shillings) placed 

 under the feet. 



At the instant of contact there were energetic muscular 

 movements, the points of contact being extensive. 



In two minutes we interrupted the circuit ; the muscles of 

 the limbs were already affected with spasmodic contractions. 



After two minutes more of completed cii'cuit, the spasmo- 

 dic contractions were again observed on breaking it, and it 

 was observed that this effect continued longer in the limb b, 

 than in that marked a. 



When the circuit was again completed, the mere contact 

 of the wet camel' s-hair pencil, applied to keep the neurilemma 

 moist, produced obvious muscular contractions, especially if 

 the pencil touched the nerve and muscle of the limb together. 

 The application of a curved platinum wire to two distinct 

 points of the nerve, produced a sensible eflPect ; but, on lay- 

 ing two portions of platinum plate on distant parts of the 

 nerve, and connecting them by a platinum wire, represented 

 at c, the effect was vei-y considerable, and sometimes seen in 

 the other limb. 



On disconnecting the platinum wires from the discs of sil- 

 ver, on which the feet were laid, and on connecting these by 

 means of a curved platinum wire, energetic movements took 

 place, an effect which was repeated four or five times, until, 

 as it would appear, the electrogenic condition was discharged. 

 On waiting a few minutes, and again making the con- 

 nection, the same phenomenon was again observed in a slight 

 form, no re-application of the Voltaic influence having been 

 made. 



In this electrogenic state, if the femora be brought into 

 contact, there ai'c convulsive movements if the points of con- 

 tact be perfectly moist. The same effect is observed if the 

 moistened nerves be connected by means of the jdatinum 

 plates ; but the platinum wires Avere insufficient for this pur- 

 pose. 



As the excitability of the frog declined, the act of break- 

 ing the circuit afl'ected the limb a, and that of remaking it 

 the limb b, more than the other. 



