EFFECT OF IRRITATION OF A POLARIZED NERVE. 417 



CONCLUSIONS. 



The effect of an irritation of a polarized nerve as compared with the 

 effect of the same irritation of the non-polarized nerve depends — 



1. On the proportion between the strengths of the polarizing and irri- 

 tating currents. 



2. On the circumstance that the irritation is to the side of the anode 

 or to the side of the kathode of the polarizing current. 



3. On the length of time that the nerve muscle preparation has been 

 exposed. 



4. On the circumstance whether the muscle is weighted or not. 



In at least two proportions of the two currents Pfliiger's results can 

 be obtained for an uncertain period of time. Another proportion re- 

 verses this effect, and gives increased excitability to the side of the 

 anode, and a diminished excitability to the side of the kathode. Other 

 proportions of the two currents may give an increased or a diminished 

 excitability to the side of both poles. And, lastly, we may have the 

 polarization failing absolutely to influence the effect of the irritation. 



APPLICATION OF THE CONCLUSIONS. 



The results obtained in the foregoing experiments would be of interest, 

 even if they had but a scientific value, but their value is much enhanced 

 by what they ^omise in enlightening our views on the pathology of the 

 nervous system. 



As respects disea es of the peripheral motor nerves, they open up an 

 entirely new field of work. Every physician who has had even the 

 least experience in electro-therapeutics must have come across cases of 

 local motor affections of the nerves, producing a paralysis, which for a 

 long time apparently resists all electrical treatment, when by changing 

 the strength of the electrical current employed a cure is effected in a 

 very short time. 



Two such cases have come under my observation. In one of these 

 the attending physican had used a constant current of very great strength, 

 and only aggravated the existing paralysis of the arm and forearm. I 

 advised and applied, daily, a constant current derived from but two 

 large Dauiel cells, and in less than a month the arm had almost com- 

 pletely recovered. 



Another case occurred during my presence in Vienna. A young girl 

 suffered from choreaic twitchings of the left hand. The application of 

 constant currents of but slight strength to the brachial plexus increased 

 tliese twitchings. When the current was increased in strength the 

 twitchings ceased, and ultimately the patient was cured. 



With the sensory nerves similar phenomena can be observed. A per- 

 son strikes his head (or some other portion of his body) against a hard 

 object, and as a result a sensation of pain remains. Now, applying a 

 constant pressure to the injured part will increase, decrease, or even 

 S. Mis. 59 27 



