REPRODUCTION AND SEX 569 



evolution make their appearance in greatest abundance in man. 

 There seems to be no secure basis for this generalisation; it seems 

 doubtful whether any generalisation of the kind is yet feasible. Karl 

 Pearson made seventeen groups of measurements of different parts 

 of the body: in eleven groups the female is more variable than the 

 male, and in six the. male is more variable than the female. More- 

 over, the differences of variability are slight, less than those between 

 members of the same race living in different conditions. Furthermore, 

 an elementary remark must be permitted. Since inheritance is bi- 

 parental, and since variation means some peculiarity in the in- 

 heritance, a greater variability in men, if true, would not mean that 

 men as such had any credit for varying. The stimulus to variation 

 may have come from the mother as well as from the father. If 

 proved, it would only mean that the male constitution gives free 

 play to the expression of variations, which are kept latent in the 

 female constitution. What is probably true is that some variations 

 find expression more readily in man, and others more readily in 

 woman. 



In regard to the mental differences between men and women we 

 must from the biological point of view confess to feeling the difficulty 

 of making definite statements until more experiments are accumu- 

 lated, and the difficulty of distinguishing between extrinsic acquired 

 differences and intrinsic innate differences. 



It has been said that men have greater cerebral variability and 

 more originality, while women have greater stability and more 

 common sense. It has been said that woman has the greater integrat- 

 ing intelligence, while man is stronger in differentiation. "The 

 feminine passivity is expressed in greater patience, more open- 

 mindedness, greater appreciation of subtle details, and consequently 

 what we call more rapid intuition. The masculine activity tends to a 

 greater power of maximum efifort, of scientific insight, of cerebral 

 experiment with impressions, and is associated with an unobservant 

 or impatient disregard of minute details, but with a stronger grasp 

 of generalities." 



But these are somewhat impressionist generalisations. What we 

 require is a great extension of experiments like those of Miss Helen 

 B. Thompson. She found that the ability to make very delicate 

 and minutely controlled movements was slightly better in men- 

 students. But may not this be connected with the greater use of 

 knives and other tools? Ability to co-ordinate movements rapidly 

 to unforeseen stimuli was clearly better in women. Women -students 

 showed a greater power of distinguishing the higher and lower 

 notes of the tuning-fork. But may this not be due to more early 

 training in piano-playing or the like ? 



The eye of the man-student was on the whole more sensitive to 

 light. The men perceived weak rays which were not seen by the 



