
ei a 

-1905.] The Structure and Function of Nerve Fibres. 347 
It is natural to turn to the electrical fishes for a further test of the possi- 
bilities dealt with above, and it is not surprising to find in them convincing 
support. Let us imagine two consecutive muscle-segments, a dim band 
and a bright band arranged together in a stout connective-tissue covering. 
Let us suppose that no intervening membrane has formed between the two 
segments, so that no considerable redistribution of the water in the two 
segments (of any consequence) can result from a localised liberation of 
electrolytes into solution. Further, suppose that a branch of the motor 
nerve terminates in the dim band, so that the transmitted negative charge of 
the nervous impulse is bestowed upon the dim band. The colloid in the dim 
band becoming negatively charged, passes into the state of desolution (ten- 
dency towards coagulation), the local osmotic pressure will rise, and 
electrolytes will diffuse into the bright band. Now, if in this arrangement, 
we have also retained the condition present in muscle, namely, that the 
positive kation of this diffusing electrolyte is of a greater relative velocity 
than the negative anion, then the positive charge will be bestowed upon the 
bright band, and the negativity of the dim band caused by the nerve 
discharge will be reinforced. Thus, a current will traverse this piece of 
tissue in the direction of the greater relative motion of the positive charge 
—from dim band to bright band. Surrounding conductors will be traversed 
by a current in the opposite direction, a current which may be described as. 
passing in the direction of the nerved end of this little organ. This, then, is. 
V//Z ee ZY. 
a 
an electrical organ, the discharge in which takes the direction defined by 
Pacini’s rule. It is just such an organ as, from what has been said 
previously, we would expect to find as the result of the transmutation of a 
muscle into an electrical organ. 







An organ, however, developed on similar lines from some other colloid 
solution than that found in muscle might be conceived to contain some other 
electrolyte, and, indeed, one in which the negative anion possessed the 
greater relative velocity. In this case, the segment of the colloid in the 
immediate vicinity of the nerve-ending would be positively charged as a 
result of desolution, and the more distal segment would be negatively 
charged by the more rapidly moving negative anion. The discharge, then, 
2A 2 
