84 LIFE OF 



by the cattle. In one square yard, at a point some hun- 

 dred yards distant from one of the old clumps, I counted 

 thirty-two little trees ; and one of them, judging from the 

 rings of growth, had during twenty-six years tried to 

 raise its head above the stems of the heath, and had 

 failed." 



The interdependence of animal upon animal, of animal 

 upon plant, of plant upon animal, is enforced in many 

 ways by Darwin. For instance, the visits of humble-bees 

 are of special importance to the welfare of red clover ; 

 humble-bees are largely destroyed by field-mice ; cats 

 largely destroy field-mice near villages, and so favoui 

 humble-bees, and secondarily red clover. Every para- 

 graph of the chapter on the struggle for existence is full 

 of suggestion, and subversive of old imaginings. But 

 Darwin's knowledge is to him slight, his ignorance pro- 

 found. Yet, he says, notwithstanding our ignorance, 

 " we may console ourselves with the full belief that the 

 war of nature is not incessant, that no fear is felt, that 

 death is generally prompt, and that the vigorous, the 

 healthy, and the happy survive and multiply." 



The great chapter on Natural Selection, or the preser- 

 vation of favourable and the rejection of injurious varia- 

 tions, is crowded with striking passages. One of these 

 vividly contrasts man's selection with nature's. " Man 

 can act only on external and visible characters : nature 

 cares nothing for appearances, except in so far as they 

 may be useful to any being. She can act on every in- 

 ternal organ, on every shade of constitutional difference, 

 on the whole machinery of life. Man selects only for his 

 own good; nature only for that of the being she tends. 



