The Destiny of Man. 27 



chief among these agencies is Natural Se- 

 lection. It has again and again been illus- 

 trated how by the cumulative selection and 

 inheritance of slight physical variations 

 generic differences, like those between the 

 tiger and the leopard, or the cow and the 

 antelope, at length arise; and the guid- 

 ing principle in the accumulation of slight 

 physical differences has been the welfare 

 of the species. The variant forms on either 

 side have survived while the constant forms 

 have perished, so that the lines of demar- 

 cation between allied species have grown 

 more and more distinct, and it is usually 

 only by going back to fossil ages that we 

 can supply the missing links of continuity. 

 In the desperate struggle for existence no 

 peculiarity, physical or psychical, however 

 slight, has been too insignificant for nat- 

 ural selection to seize and enhance; and 

 the myriad fantastic forms and hues of an- 

 imal and vegetal life illustrate the seeming 

 capriciousness of its workings. Psychical 

 variations have never been unimportant 



