246 TIIE STRUGGLE FOR THE LIFE OF OTHEKti. 



age which cuts down to the very root of being in 

 everything that lives. 



No theme of equal importance has received less 

 attention than this from evolutionary philosophy. 

 The single problems which sex suggests have been 

 investigated with a keenness and brilliance of treat- 

 ment never before brought to bear in this mysterious 

 region ; and Mr. Darwin's theory of sexual selection, 

 whether true or false, has called attention to a multi- 

 tude of things in living Nature which seem to find a 

 possible explanation here. But the broad and simple 

 fact that this division into maleness and femaleness 

 should run between almost every two of every plant 

 and every animal in existence, must have implications 

 of a quite exceptional kind. 



How deep, from the very dawn of life, this rent 

 between the two sexes yawns is only now beginning 

 to be seen. Examine one of the humblest water 

 weeds the Spirogyra. It consists of waving threads 

 or necklaces of cells, each plant to the eye the exact 

 duplicate of the other. Yet externally alike as they 

 seem, the one has the physiological value of the male, 

 the other of the female. Though a primitive method 

 of Reproduction, the process in this case foreshadows 

 the law of all higher vegetable life. From this point 

 upwards, though there are many cases where repro- 

 duction is asexual, in nearly every family of plants a 

 Reproduction by spores takes place, and where it does 

 not take place its absence is abnormal, and to be 

 accounted for by degeneration. When we reach the 

 higher plants the differences of sex become as marked 

 as among the higher animals. Male and female 

 flowers grow upon separate trees, or live side by side 



