ELECTROTHERAPY 283 



to be changed in certain respects by electricity. In general the 

 following effects are recognized: 



1. The stimulant action is produced most strongly by the 

 induced (faradic) current. It causes burning of the skin (cutaneous 

 irritation), stimulation of the sensory and motor nerves, muscular 

 contraction, dilation of the blood-vessels (stimulation of the vaso- 

 dilators), increase of gland activity and of metabolism. Electricity 

 therefore operates as a stimulant to most of the organs of the body. 



2. The electrotonic action consists in the alteration of the 

 physiological electrotonus, i.e., a change in the susceptibility of 

 the nerves (anelectrotonus, catelectrotonus). To this are probably 

 due in great part the curative results of electrotherapy in nerve 

 diseases. The electrotonic action of the continuous current espe- 

 cially is sedative, reducing the receptivity of the nerves. 



3. A chemical action is undoubtedly produced by the electric 

 current, especially in the region of the poles (anode, cathode). It 

 acts first of all upon the fluids (serum, blood) and upon the salts 

 contained in them. As is well known, salts and other compounds 

 (water) are separated by electrolysis into their positive and nega- 

 tive elements and the positive (alkaline) elements are attracted 

 by the negative pole or cathode while the negative elements (acid) 

 are attracted by the positive pole or anode. The electric current 

 in muscles and nerves is probably due to a similar combination 

 of chemical opposites. 



4. A cataphoric action is manifested by substances which ordi- 

 narily are not diffused through the tissues of the body becoming 

 diffusible under the influence of the electric current. Because of 

 the results obtained in experiments with potassium iodide and 

 cocaine, it is assumed that pathological products also become 

 diffusible. 



The so-called catalytic (alterative) action appears to consist 

 essentially of a stimulation of the vasomotor and trophic nerves 

 and consequently falls under the first-named action. 



Uses. — In veterinary medicine, electrotherapy is indicated in 



