THE STRUGGLE FOR THE LIFE OF OTHERS 323 



to its existence, and largely the condition of it, is 

 the even more beautiful development whose pro- 

 gress we have now to trace. The basis of this 

 new development is indeed far removed from the 

 mutual relations of sex with sex. For it lies 

 in maleness and femaleness themselves, in their 

 inmost quality and essential nature, in what they 

 lead to and what they become. The superstruc- 

 ture, certainly, owes much to the psychical relations 

 of father and mother, husband and wife, but the 

 Evolution of Love began ages before these were 

 established. 



What exactly maleness is, and what femaleness, 

 has been one of the problems of the world. At 

 least five hundred theories of their origin are already 

 in the field, but the solution seems to have baffled 

 every approach. Sex has remained almost to the 

 present hour an ultimate mystery of creation, and 

 men seem to know as little what it is as whence 

 it came. But among the last words of modern 

 science there are one or two which spell out a 

 partial clue to both of these mysterious problems. 

 The method by which this has been reached is 

 almost for the first time a purely biological one, 

 and if its inferences are still uncertain, it has at 

 least established some important facts. 



Starting with the function of nutrition as the 



