NEW CONCEPTIONS IN SCIENCE 



It soon was clear that Dr. Mathews was right 

 in his belief, that it was the negative ions which 

 made the frog's legs jerk. Their action through 

 the nerve, and on the muscle direct, is the same. 

 The nerve, then, must somehow effect a release of 

 negative ions at the point where it blends with the 

 muscular tissue. How? 



If, said Dr. Mathews, the negative ions be in 

 excess in the solution, and the positive and negative 

 ions in the nerve be just balanced, the effect would 

 be the precipitation of the first layer of colloid 

 particles bearing positive charges and in contact 

 with the solution. This would release a certain 

 number of negative ions lying next in the nerve 

 sheath, and these in turn would precipitate the 

 adjoining colloids. This would result in a kind of 

 wave of precipitation, travelling along the nerve, 

 and at the end would be a set of free negative ions, 

 ready to call the muscle into action. The nerve 

 impulse, then, would appear to be a consecutive 

 series of precipitations. 



But it remained to be explained how a mere 

 mechanical stimulus, a push or a blow, could set up 

 this wave. This can be accounted for by supposing 

 the effect is the same as when rain-drops on a win- 

 dow are made to coalesce when the window is struck. 

 Two or more colloid particles coming together would 

 have their surfaces reduced, hence their electrical 



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