178 MUSCULAR CURRENT. L.ECT. IX. 



an insulating varnish, take hold of the tube with the hand, 

 and afterwards bring any two parts of the body, whose 

 electric state we wish to examine, in contact with two dif- 

 ferent and sufficiently distant points of the nervous filament 

 of the galvanoscopic frog. 



If we take the precaution of not touching the body with 

 any portion of the muscle of the leg, and if the limb be well 

 insulated from the hand, we may be certain that the con- 

 traction which the galvanoscopic frog suffers, is due to a 

 current produced in the body touched, and that the nerve 

 only conducts it, and renders it evident by the contraction 

 of the muscle. 



Electric Current in Muscles. Furnished with a frog, thus 

 prepared, I take a living animal, a pigeon for example, 

 slightly cut its pectoral muscle, after having carefully re- 

 moved the integuments, and introduce into the wound the 

 nerve of the galvanoscopic frog. 



You observe the contraction of the frog. If you reflect 

 on the arrangement, you will be satisfied that it is absolutely 

 necessary to touch two distinct parts of the pectoral muscle 

 of the pigeon, with two different parts of the nervous fila- 

 ment. If I apply the extremity of the nerve to the bottom 

 of the wound, and another portion of the nerve to the lips 

 of the wound, or, better still, to the external surface of the 

 muscle, the frog continually contracts. This experiment 

 clearly demonstrates the presence of an electrical current, 

 which circulates in the nerve, since it is necessary to form a 

 circuit in which the nerve forms a part. If you have any 

 doubt that the contractions of the frog are really excited by 

 a current due to the different parts of the muscle of the ani- 

 mal, you will soon be convinced, by finding that no con- 

 tractions are produced when I touch two different parts of 

 the nerve with one liquid, or with a perfectly homogeneous 

 conducting body. 



