CURRENT OF DEATH 



171 



each of which was nearer than the last by 5 mm. to the dead 

 end, which was to the left The same process was now re- 

 peated, the successive 

 readings however being 

 taken towards the right 

 or living end. At each 

 point, the electro-motive 

 difference was balanced 

 by the potentiometer. 

 This straight form of 

 potentiometer had a 

 scale divided into one 

 thousand parts (fig. 1 14), 

 and when its terminal 

 electro-motive force was 

 adjusted to I volt, each 

 division of the potentiometer was equal to 'OOi volt. The 

 following table gives the results obtained : 



EIG. 1 14. Straight Form Potentiometer 



A B is a stretched wire with added resistances, 

 R and R'. s is a storage cell. When the 

 key, K, is turned to the right, one scale 

 division = -ooi volt, when turned to the 

 left one scale division = -01 volt, p is the 

 plant. 



Here, also, as in the case of natural death, we find a point 

 in the dying tissue which is most negative. From the curve 

 given in fig. 115, it will also be seen that as we pass away 

 from this point in either direction towards the living or dead 

 area, we find an increasing positivity ; the curve for the dead 

 portion is, however, much steeper than that for the living. 

 Thus two points, one 1*5 cm. to the left in the dead tissue, 

 and another 5 cm. to the right in the living tissue, are 

 iso-electric. But while the maximum positivity of the living 



