MUSCLE-NERVE. 



and fat. In this case the electrode, anode or kathode, is brought 

 into as close relation to the nerve as possible. Only a small por- 

 tion of the current will traverse the nerve, longitudinally. The 

 greater part of the current will traverse the nerve diagonally, form- 

 ing current loops which spread through the tissues, finally concen- 

 trating to pass through the nerve again to the other electrode. 



Those points at which the current enters the nerve are known as 

 physiological anodes, and those where the current leaves the nerve, 

 as physiological kathodes. Thus, at each pole groups of physio- 

 logical anodes and kathodes are found. The contraction of the 

 muscle which occurs when the current is closed represents irritation 

 at the physiological kathode. That contraction occurring at the 

 break of the current represents irritation at the physiological 

 anode. 



Since there are both physiological anodes and kathodes at each 

 pole, any one or more of the following results may be obtained 

 through the opening or closing of the constant current: 



1. Anodic Closing Contraction. Contraction following the 

 change developed at the physiological kathode beneath the phys- 

 ical anode. 



2. Anodic Opening Contraction. Contraction following the 

 change produced in the nerve at the physiological anode beneath 

 the physical kathode. 



3. Kathodic Closing Contraction. Contraction following the 

 change produced in the nerve at the physiological kathode beneath 

 the physical kathode. 



4. Kathodic Opening Contraction. Contraction following 

 the change produced in the nerve at the physiological anode be- 

 neath the physical kathode. 



The following abbreviations for these contractions, from i to 4 

 respectively, are used: ACC, AOC, KCC, KOC. 



KCC and ACC are stronger than KOC and AOC. KCC is 

 stronger than ACC, and AOC is stronger than KOC. 



The effect of change of strength of current is shown in the fol- 

 lowing table: 



[43] 



