OF SELBORNE 183 



the young to seek for new abodes : and the rivalry of the males, 

 in many kinds, prevents their crowding the one on the other. 

 Whether the swallows and house-martins return in the same 

 exact number annually is not easy to say, for reasons given 

 above : but it is apparent, as I have remarked before in my 

 Monographies, that the numbers returning bear no manner of 

 proportion to the numbers retiring. 



LETTER XL. 



TO THE SAME. 



Selborne, June 2, 1778. 

 DEAR SIR, 



THE standing objection to botany has always been, that it is a 

 pursuit that amuses the fancy and exercises the memory, without 

 improving the mind or advancing any real knowledge : and where 

 the science is carried no farther than a mere systematic classifica- 

 tion, the charge is but too true. But the botanist that is desirous 

 of wiping off this aspersion should be by no means content with 

 a list of names ; he should study plants philosophically, should 

 investigate the laws of vegetation, should examine the powers 

 and virtues of efficacious herbs, should promote their cultivation ; 

 and graft the gardener, the planter, and the husbandman, on the 

 phytologist. Not that system is by any means to be thrown aside ; 

 without system the field of Nature would be a pathless wilderness ; 

 but system should be subservient to, not the main object of, pursuit. 

 Vegetation is highly worthy of our attention ; and in itself is 

 of the utmost consequence to mankind, and productive of many 

 of the greatest comforts and elegancies of life. To plants we 

 owe timber, bread, beer, honey, wine, oil, linen, cotton, &c., 

 what not only strengthens our hearts, and exhilarates our spirits, 

 but what secures from inclemencies of weather and adorns our 

 persons. Man, in his true state of nature, seems to be subsisted 

 by spontaneous vegetation : in middle climes, where grasses 

 prevail, he mixes some animal food with the produce of the 

 field and garden : and it is towards the polar extremes only that, 

 like his kindred bears and wolves, he gorges himself with flesh 

 alone, and is driven, to what hunger has never been known to 

 compel the very beasts, to prey on his own species. 1 



1 See the late Voyages to the South-seas. 



