APPENDIX D 225 



parental and sexual love) none apparently are gratified without 

 the aid of rational action. Consider, for instance, how greatly 

 the instinctive appreciation of female beauty is modified by the 

 acquired factor ; there are savage tribes who mutilate, to render 

 beautiful as they think, the faces of their women to a frightful 

 degree. Consider, again, how much there is of the rational {e.g. 

 the co-ordination of her muscles) in the mother's care of her 

 offspring. 



As in the case of physical characters, no systematic attempt 

 has hitherto been made to differentiate between the mentally 

 acquired and the inborn. As a result, much confusion and 

 inaccurate thinking is manifest in writings, scientific and other- 

 wise. I propose to deal with these to some extent presently ; 

 but first it would be interesting to trace, in however slight a 

 manner, the evolution in animals of the power of acquiring 

 mental traits. But, even before doing this, one other digression 

 I may permit myself, since it has an important bearing on much 

 that follows. It has been maintained that acquired characters, 

 mental and physical, are transmissible. I will not here pause to 

 consider whether such characters as I have ventured to denominate 

 "enforced," nor whether such characters as result from the 

 complete or partial reproduction of lost parts, are transmissible. 

 The battle has been fought in countless publications, and I do 

 not know that I have now anything very new or original to add, 

 but I should like to say a little concerning the alleged trans- 

 missibility of such characters as result from use or experience, 

 for instance, the acquired enlargement of the blacksmith's muscle 

 through use, or the mental change evolved in the acquirement of 

 a knowledge of mathematics through experience. Characters like 

 these are held by a section of biologists to be transmissible, in 

 part at least. But when a parent acquires such characters, they 

 reappear in the child only in response to stimulation similar to 

 that which caused them to arise in the parent. For instance, 

 without such stimulation the child gets neither the enlarged 

 muscles nor the knowledge of mathematics; in fact, he must 

 in all cases acquire such characters afresh — from which it is 



P 



