AS REGARDS EXCITABILITY OP NERVE FIBRES. 201 



Most of those who have taken up the subject of nerve 

 action from the experimental side, appear to have had 

 a very imperfect accpiaintance with the structure of 

 the tissue upon which they were experimenting. The 

 transmission of electric currents through the nerves 

 after the death of a recently killed animal, is a very 

 rough operation, and indeed very different in many 

 particulars from the transmission of the natural cur- 

 rents, whatever may be then* nature, along the axis 

 cylinder, while it remains in connexion with its cen- 

 tral cells during the life of the animal. 



If we were to take a bundle of several marine 

 cables, and smear the gutta-percha investment care- 

 lessly over the cut ends of the copper wire cores, at 

 a distant part of the circuit, and then transmit a most 

 powerful cuirent through the deranged wires, we 

 should not find the needles acting as they did when 

 very delicate currents were u\ade to traverse an in- 

 dividual wire. The differences observed might induce 

 some to conclude that the current by which the in- 

 strument was influenced in the normal state, was 

 totally distinct in its nature from that much more 

 powerful current which gave rise to the much greater 

 but irregular and unmeaning disturbances. This 

 reasoning is applicable to the experiments in which 

 strong electric currents have been transmitted along 

 compound damaged nerve trunks. 



251. Fallacy of the argument based upou the ex. 

 citatollity of nerve fibres. — It has been said that the fact 

 that nerve loses its excitability without losing its power 

 of conducting electricity, is a fatal objection to the 

 doctrine that the nerve current transmitted during life 

 is of the nature of electricity. But many things seem 

 to have been entii'ely overlooked by those who urge 

 this argument with so much confidence. Is it not 

 obvious that soon after death, the bioplasm which is 

 instrumental during its life in maintaining an equable 

 flow of nutrient fluid through the tissue adjacent to 



