288 



ELECTRO-PHYSIOLOGY 



CHAP. 



observed, under similar conditions, with both descending and 

 ascending closure, in the nerves of cooled frogs, on keeping 

 them for 1224 hours before the experiment, with the skinned 

 legs to which they are connected, in 0*6 J ETaCl at room 

 temperature. 



TABLE I. 



The gradually increasing concentration of the saline, from 

 evaporation, seems here to increase the previous inclination of the 

 nerve to tetanus, on exciting it with the constant current, as 

 appears directly from observation of the muscle connected with 

 it, which falls at closure of both descending and ascending 

 currents into prolonged and vigorous tetanus. The galvanometer 

 effects under the same conditions as before are proportionately 

 stronger, and negative deflections of 1520 degrees with de- 

 scending, 47 degrees with ascending closure, are not infrequent, 

 on leading off from the lower (transverse) end of such a pair of 

 nerves. The diminution of effect on shortening the intermediate 

 tract, by moving the galvanometer contacts away from the cross- 

 section, is therefore all the more striking. 



If deflections in the direction of katelectrotonic variations 

 are accordingly perceptible at a greater distance from the 

 kathode, only in the case of an initial P.D. between the contacts, 

 then in uninjured, isoelectric frogs' nerve, at maximal distance 



