78 



THE SIGNS OF LIFE 



[LECT. 



The response of skin is on a precisely similar schema, 

 thus : 



Electrical organ 

 of Torpedo. 



Dorsum 

 Venter 



Frog's Skin. 



Eoct. surfd.ce 



Inb. surface 



Response of 

 living organ. 



Polarisation 

 currents of- 

 dead organ. 



FlG. 35. Diagram exhibiting the similarity between an electrical organ and the 

 skin as regards their normal electrical responses during life (and the polarisation 

 effects after death). 



And as you see from the diagram (or from the experiment that 

 is set up to reproduce it), we are justified in saying of the skin 

 that it discharges in a direction of its own while it is alive, and 

 exhibits after death the ordinary polarisation of a non-living 

 electrolyte. It responds better, as you may notice, to an anti- 

 than to a homodrome excitation, agreeing in this respect with 

 the organ of Malapterurus (Gotch), but disagreeing, I may add, 

 from that of Torpedo (du Bois-Reymond). 



48. The organ-discharge. The essential component of an 

 electrical organ is a disc, upon one surface of which a nerve 

 twig ramifies, while the other surface is vascular. The electrical 

 organ consists of piles of such discs, surface to surface, like the 

 elements of an old-fashioned voltaic pile ; its structure, as well 

 as the great electro-motive force of the discharge, suggest that 



