HOW THE BRAIN THINKS 



amoeboid motion, as it is called, that a nerve- 

 wave travels. And yet others have found no 

 need of any such protractions and retractions 

 whatever. They compare a nerve - wave to an 

 electric current, and say that just as there is a 

 field of disturbance round every electric current, 

 or body, so probably there is a field of disturbance 

 round every nerve in action, and that this dis- 

 turbance may affect the close-lying nerves. One 

 difficulty with this theory is that it would imply a 

 weakening of the nerve-current as it flies from one 

 nerve-end to the next, while, in some cases at least, 

 the fact seems just the reverse ; a nerve- wave often 

 seems to gain power as it rushes along, so that an 

 impulse, very weak at the beginning, may re- 

 sult in a bodily cataclysm, meaning paralysis or 

 death. 



An ingeniously minded Frenchman, M. Jules 

 Soury, of the Sorbonne, has suggested a solution 

 of all these conflicting ideas by supposing that 

 both sides may have a part of the truth. In other 

 words, he believes that in some cases there is con- 

 tact, or continuity, and that in others there is a 

 leap. And from this he draws a possible con- 

 clusion that is of extreme interest. He suggests 

 that in the case of unconscious nervous or cerebral 

 action (by far the greater part of the nervous 

 activity) there is contact; that we become aware 



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