120 STUDIES IN ELECTRO-PHYSIOLOGY: 



The foregoing may be considered as direct evidences of 

 the universality of the law which governs all living things. 

 The examples I am about to cite cannot be said to fall, 

 without question, into this category, because while the 

 structures exhibit a striking resemblance, the organs are 

 not in all cases designed for the same purpose or function. 

 A little reflection, however, will show that, so far as structure 

 is concerned, it differs only in detail, in more or less perfec- 

 tion of finish or development ; the underlying principle is 

 there. Let us call them coincidences for the time being, 

 and trust to future investigation to link them in some 

 measure more closely together. It may here be said that 

 only from the " living " can any reversal of sign, implying 

 an electrical system, be obtained. In the " non-living " 

 there is no difference of potential unless introduced by 

 some exterior vehicle of energy. 



ANIMAL 



VEGETABLE 



Fig. 36. 



Ganglion cell with nerve process 

 (human). 



Fig. 37. 



Original spore of Vaucheria Set- 

 silis. (After Sachs.) 



Fig. 38. 



Section of spinal cord (human). 

 (After Schdfer.) 



Fig. 39. 



Diagrammatic sketch of trans- 

 verse section through portion of 

 root of Phaseolus muUiflortts. (After 

 Sachs.) 



