450 



EDWAED HORNE CRAIGIE 



which shows that, in spite of irregularities, there is no evidence 

 of any definite difference in the material as a whole between the 

 two stocks. 



Chart 4 shows the result of grouping the sexes separately and 

 comparing them. It will be seen that the females show a distinct 

 tendency to a richer vascular supply than the males, though the 

 difference is neither very great nor very constant. 



12 3 4 3 



Chart 4 Graph showing the relation between the sexes in point of vascularity. 

 Male, #; female, +. Numbers of regions as in chart 2. 



DISCUSSION 



The attempt to interpret in terms of function the above ana- 

 tomical observations leads us at once to the question of the 

 importance of metabolic processes in nervous activity, and so 

 to the even more fundamental question of the essential nature 

 of the nervous impulse. Here we find ourselves in a sea of 

 controversy, of varying opinions, and of contradictory 

 evidence. 



