308 PROGRESS OF SCIENCE IN THE CENTURY. 



of the cortex are " like a group of Amoebae having a 

 talk together," as it has been romantically expressed, 

 may be a fascinating one, but there is very little 

 scientific evidence in its favour. 



(d) Not less difficult to answer is the question 

 " What part do the nerve-cells play in relation to the 

 conducting or impulse-transmitting function of the 

 nerve-fibres ? " One extreme is expressed in the an- 

 swer — for which the explorer ISTansen was first re- 

 sponsible — that the substance of the nerve-cell or 

 ganglion-cell has merely a nutritional value, but this 

 is almost contradicted by the facts known in regard 

 to nerve-fatigue. The other extreme is expressed in 

 the answer, for which there is much more to be said, 

 that the specific-nervous functions have their seat in 

 the substance of the ganglion-cell. Between these 

 may be placed the view that the nervous processes 

 have their physical basis in a functionally homoge- 

 neous fibrillar substance continuous , through the 

 whole of the neuron. This again is one of the 

 problems handed on unsolved to the twentieth 

 century. 



(e) But we must not pass over the line of in- 

 vestigation which first became prominent in a re- 

 search by Prof. Hodge — " A microscopical study of 

 changes due to functional activity in nerve cells " * 

 and has since been pursued by many, — Mann, Lu- 

 garo, ISTissl, Goldschneider and Flatau, Marinesco, 

 Fick, Guerrini, and others. 'Not many years ago 

 the possibility of demonstrating the structural effects 

 of nerve-fatigue, would have seemed an impossibility ; 

 it may now he called an achievement. Whether we 

 follow Hodge in showing the difference between the 



* Journal of Morphology, VII., 1892. 



