On Kkin ('in- rents. 



185 



FIG. 14 



B C A 



Excitation. 



i i i 



Bight foot. 12 hours. 4 L. 1000 + 



12i liours. 4 L. 10,000 + 



OOI 



nil/. 



OO4 



-O05 



Response ingoing at B. 



A. 



Ri-sponse outgoing at B. 



After this series of four trials at 10,000, a, series of four trials at 

 1000 gave no effect. On transfer of an electrode to fresh pad an 

 ingoing response was observed after excitation at 1000. 



Fallacy to be avoided. 



The longest period at the end of which I have detected unmis- 

 takable physiological response of a surviving pad has been 7 days 

 post mortem. I have not, however, sought to follow out the reaction 

 to its last remaining trace so as to determine a maximum duration 

 of survival, because with declining voltage of reaction the disturbing 

 effects of polarisation counter-currents become more and more appx- 

 rent. At a comparatively early period the response to single shocks 

 disappears, and the galvanometer, if sensitive, manifests only polari- 

 sation effects contrary in direction to the test shocks. At this 

 period tetanisation by currents alternating in direction will still 

 bring out a true summated outgoing effect with both pairs of direc- 

 tions of currents ; under these conditions the effect of polarisation is 

 relatively smaller. But at a later period, as the life of tissue is 

 coming to an end, and the response reaches a value to be measured in 

 ten thousandths of a volt, the disturbing influence of polarisation again 

 becomes apparent. In this case the deflection after tetanisation is 

 reversed with reversal of direction, and a resultant due to superior 

 polarisation by make is witnessed in the direction of break. The 

 shortest period after death at which I have observed this state has been 



