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ELECTRO-PHYSIOLOGY 



CHAP. 



Jcatelectrotonic effect. Under favourable circumstances, vigorous 

 preparations that have been cautiously narcotised will completely 

 recover their normal properties, including that of conductivity in 

 the nerve ; in other cases there is, on the contrary, a perceptible 

 loss (as expressed, e.g. in preparations of cooled frogs, by the 

 frequent suppression of the negative variation of the nerve current 

 described above as the galvanic expression of the make or break 

 persistent excitation, at the close of narcosis so that the nerve 

 reacts precisely like a preparation from a warmed frog). With 

 tetanising induction currents also there is frequently a visible and 

 permanent diminution of the negative variation. 



The figures contained in the following table will illustrate 

 these facts : they refer to deflections observed under the same 

 experimental conditions as the former series. NS = strength of 

 the nerve current ; E, number of (Daniell) cells ; ZS, length of 

 the intermediate tract ; SR, direction of current. 



