ELECTRICITY IN MEDICINE. 
535 
In practice it must be remembered that the electricity does not 
penetrate deeply into the interior of bodies, but seeks the surface, 
therefore the greater the surface the greater the amount con¬ 
tained; and further, that it has a marked tendency to accumulate 
and discharge in points. Possibly the shoes of the horse are the 
discharging points and the earth the receiver. In such a case 
“ insulative ” foot plates or floors may be required in equine elec¬ 
tro-therapeutical practice, while the conducting powers also of 
the different forms of litter require some consideration by the 
veterinarian. 
As a suggestion to those building or equipping veterinary in¬ 
firmaries in large cities, it might be mentioned that there is no 
reason why the electric current of ordinary lighting wires 
should not be introduced into these hospitals. 
This current is a ‘‘constant current” easily regulated in quan¬ 
tity and quality by mechanical fixtures, so as to be utilized for al¬ 
most all therapeutical purposes, including the galvano-cautery. 
With such a constant electrical supply as this an equipment of 
suitable electrodes for permanent use is but a small item of ex¬ 
pense, while the dangers of the system are easily minimized in these 
days of advanced science. 
Again, “ the strange fluid,” like all other fluids, seeks its own 
level, and it is therefore customary to speak of “ positive ” and 
u negative,” potentials. Two agents charged of different potentials 
act positively and negatively to each other. 
I shall not attempt to describe any of the countless varieties of 
batteries ; they are too numerous and too complex. The cells of 
certain fishes even are looked upon as battery cells, and justly so, 
for they possess the power of magnetizing soft iron and of deflect¬ 
ing the galvanometer. 
Galvanism and faradism require some allusion. 
The galvanic, voltaic, or chemical current is generated by con¬ 
tact of dissimilar bodies in the presence of heat or chemical ac¬ 
tion. Thus, when two metals are placed in a liquid which acts 
more strongly upon the one than the other, a difference of their 
“ potentials ” results, and if now they be connected by metallic 
wires the electricity flows from the higher to the lower potential: 
