266 On the Effects of Certain Physical and 



that of the mere " making'' or " breaking" that circuit. 

 The effect is also considerable if the circuit be first broken, 

 and the wires then connected. 



We prepared a frog, as in fig. 3, and placed the platinum 

 wires and plates so as to complete the Voltaic circuit, includ- 

 ing the lumbar nerves. In two minutes we broke the cir- 

 cuit and connected the wires ; there were spasmodic move- 

 ments of the limbs. We then separated the wires from all 

 contact with zinc and silver, and connected them, still with 

 spasmodic movements, though less than before. We now 

 removed these wires, and replaced them by others, which 

 had never formed a part of the Voltaic circuit. There wei*e 

 still spasmodic movements, though slight. 



The wires were again and again exchanged, with the same 

 phenomena. 



It remains to determine, by a new and careful series of 

 experiments, the precise rationale and the influence of a 

 residual Voltaic influence, or of the electrogenic state of the 

 nerves, in these experiments ; an inquiry which I only post- 

 pone for a time. 



It does not influence the result whether the "wires be con- 

 nected near to, or distant from, the battery or the subject of 

 experiment ; or whether the zinc and silver be made to touch 

 in one of the cells, or whether the current be pursuing a 

 parallel but similar or dissimilar course, as in fig. 9 and 10, 

 this connection being made between a and b, or between c 

 and d; or, lastly, whether these connections be made between 

 either wire and the nerve, either included between the two 

 wires, or above or below, or so exterior to either — facts of 

 an extraordinary character in many points of view. 



Ex. 12. Similar phenomena are observed if the experi- 

 ment be performed in the following manner : — 



Let the lumbar and femoral nerves be applied over the 

 zinc and silver arc, as in fig. 8. This figure represents the 

 galvanoscopic frog, and without addition, is identical with 

 that in Plate 1., fig. 4., in Signior Matteucci's work.* On 

 making contact at a and e, contractions are observed in the 

 limb. 



* Traite des Phenomenes Electro-Physiologiques. 



