MUSCULAR ELECTRIZATION. 



45 



I use the following method of discliarging the two electricities, 

 accumulated in a Leyden jar, upon the muscle that I wish to 

 excite, and of graduating the force in such a manner as not 

 to produce a general shock. 



The apparatus necessary consists of an electric machine, a 

 Leyden jar, and a Lane's electrometer placed upon the table of 

 the machine. 



The interior coating of the Leyden jar, A (fig. 2), is placed in 

 connection with the arms, c, of the conductor of the electric machine 

 B, by means of a conductor D. This interior coating also com- 

 municates with E, the knob of one of the horizontal branches of 

 the electrometer. This branch is insulated by the glass upright 

 F, on which it rests. The external coating of the jar is connected 

 by the conductor G' with the upright H, which communicates with 

 the second branch of the electrometer. Two excitoi's, terminating 

 in the knobs J and K, mounted on long insulating handles of 

 glass, are placed in connection, J with the branch H', K with the 

 extremity L, of the conductor of the electrical machine. 



Fig. 2. 



All things being thus arranged, the operator applies the exciter 

 J, which receives the positive electricity of the exterior coating of 

 the jar, to a point of skin over the muscle that he wishes to make 

 contract ; and when he desires to excite the contraction, he brings 

 the other exciter, K, which receives the negative electricity of the 

 interior coating, nearly but not quite in contact with the skin, over 



