£03 



Voltaic currents and their Therapeutic application, 

 of which the following is an abstract. To render the subject 

 thoroughly intelligible, he began by describing the requisites 

 of action iu the electro-motor or voltaic battery : 1st, a liquid 

 capable of decomposition by electricity; 2nd, a metal, the 

 oxide of which is soluble in the same liquid ; and 3rd, another 

 metal incapable of being acted upon by the liquid, but a con- 

 ductor of the electricity presented to it. In proportion as 

 these (the electrolyte, the active and the conducting plates, 

 which form the battery) perform their respective office more or 

 less perfectly, do we obtain powerful or feeble currents when 

 contact between the two plates is established and the circuit 

 completed by the decomposing fluid. 



He then considered the effects of extending, by means of 

 coils of copper wire, the distance required to be traversed by 

 the electric current. When short connecting wires unite the 

 plates of an electro- motor, no spark is visible at the moment 

 contact is made, and but a feeble one when contact is broken ; 

 but when the wire is considerably extended a bright spark is 

 visible, and if the human body is made part of the circuit a 

 shock is sustained, proving that a current is thus established, 

 independent of that produced by the battery itself. Again, 

 when a current is established in a wire, and a second wire 

 with closed ends is placed near the first, when the contact with 

 the battery is broken an induced current is established in the 

 second wire. Upon renewal of contact another current is in- 

 duced in the seco:jd wire, passing in the opposite direction 

 to the former current and to that of the battery. Upon the 

 principles laid down, instruments are constructed for the 

 therapeutic application of voltaic electricity. These are either 

 primary or secondary coil machines, alike in appearance but 

 different in the arrangement of the insulated wire. The 

 former represents the single wire referred to as connecting the 

 active and decomposing metallic plates, having in its axis a 



