ANIMAL ELIX'TRICITV. — LKCTURE IV. 79 



(4) That during the passao-e of the constant current 

 excitabiHty is depressed at and near the anode. 



These four propositions, specially applicable to 

 nerve, express a very general law, and cover more 

 particularly the case of muscle — of heart-muscle as 

 well as of ordinary muscle. Subject to a possible 

 exception in the case of non-fibrillated protoplasm, 

 they express the law of response of living matter to 

 electrical currents. 



I have been at some loss how most briefly to 

 present to you an experimental illustration of these 

 two pairs of principles. The obvious and orthodox 

 object of experiment, a nerve-muscle preparation of a 

 frog, will not serve the whole purpose — for, while it 

 would do well enough to exhibit augmented kathodic 

 and diminished anodic excitability, it would afford no 

 direct and evident proof of kathodic make excitation 

 and of anodic break excitation. 



I shall, therefore, have recourse to a less orthodox, 

 and, in one particular, more complicated object, viz., a 

 nerve-muscle preparation of a man, selecting for the 

 purpose the ulnar nerve of my own forearm and the 

 muscles to which it is distributed — these are, among 

 others, several of the Hexor muscles of the wrist and 

 fingers. 



ExperiiJieiit. — I have connected myself with a bat- 

 tery by means of a large flat electrode at the back of 

 the neck ; with the knob of the other electrode held by 

 its insulating handle in my right hand, I feel about for 



