38 NATURAL HISTORY 



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. 



DEAR SIR ; SELBORNE, June 2, 1778. 



THE standing objection to botany has 

 always been, that it is a pursuit that amuses 

 the fancy and exercises the memory, with- 

 out improving the mind or advancing any 

 real knowledge : and, where the science is 

 carried no farther than a mere systematic 

 classification, 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 inves- 



