1902.] 



On Skin Currents. 



383 



On the other hand, I have observed a case, that of the hen's egg, in 

 which induction shocks give a similar considerable increase of con- 

 ductivity which I find it difficult to understand otherwise than as an 

 effect of water transport from electrode to shell at the anodic side, and 

 from contents to shell at the kathodic side. 



I am constrained therefore to leave undetermined the possible 

 influence of kataphoric action on skin resistance until I shall have 

 found means of investigating the phenomenon further. 



Alterations of temperature produce alterations of resistance of the 

 skin as of any moist conductor, viz., augmentation of resistance with 

 lowered temperature, and diminution of resistance with raised tem- 

 perature. In the case of the living skin (as in that of some other 

 living tissues) I have witnessed at the moment of congelation and on 

 subsequent thawing, two well-marked effects that appear to be most 

 significant of a phenomenon of dissociation. At a critical temperature 

 ( - 4° to - 6° of the cooling chamber) a sudden electromotive dis- 

 charge takes place, attributable to the sudden excitation or explosion 

 of living matter in the act of congelation. Subsequently, on return of 

 the frozen skin to the original temperature, the resistance is very 

 much reduced, a change which is attributable to mechanical or chemi- 

 cal dissociation of the previously frozen tissue-elements. 



Thus, e.g., in Experiment 4209 the resistance of the skin (corrected 

 for electrode resistance) at 18° was 150,000 ohms before congelation, 



Figl 4 (4209). — Skin No. Ill, 2nd day after excision. Skin gradually cooled by 

 surrounding the skin-chamber with a freezing mixture. Sudden electromotive 

 discharge (outgoing current) at a temperature of —6° inside the skin-chamber. 

 Before freezing, the + responses to + and — single induction shocks were 

 + '004 and +0 -008 volt. After freezing, the + responses were absent, being 

 replaced by small — and + polarisation effects. On recongelation no second 

 discharge was observed. 



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