DARWIN. 83 



Thus every animal and plant may be said to struggle 

 for existence with those with which it competes for space, 

 food, light, air. The numbers are kept down by heavy 

 destruction at various periods of life. Take the case of 

 seedling plants. Darwin had a piece of ground three feet 

 long and two feet wide dug and cleared, so that no grown 

 plants existed to check the growth of seedlings of native 

 plants as they came up. He counted and marked all 

 that came up, and out of 357 no fewer than 295 were 

 destroyed, chiefly by slugs and insects. So in a little plot 

 of long-mown turf, allowed to grow freely, out of twenty 

 species nine perished in the struggle. Many further per- 

 sonal observations of the author are given : such as that 

 the winter of 1854-5 destroyed four-fifths of the birds in 

 his own grounds ; that he has sometimes failed to get a 

 single seed from wheat or other plants in his garden. 



On the estate of a relative in Staffordshire the changes 

 consequent on planting several hundred acres with Scotch 

 fir were remarkable. In twenty-five years twelve species 

 of conspicuous plants, and six different insectivorous birds 

 had become settled and flourishing inhabitants in the 

 plantations. The characteristic of the philosopher, who 

 sees in the unconsidered trifles of others the material for 

 his choicest discoveries, is well exemplified in his mode of 

 observing the results of enclosure near Farnham, in Surrey. 

 Here a multitude of self-sown firs sprang up in the en- 

 closures, and Darwin went to examine into the cause of 

 the strange phenomenon. Not a fir was in sight except 

 some distant clumps. " But on looking closely between 

 the stems of the heath, I found a multitude of seedlings 

 and little trees, which had been perpetually browsed down 



