2io NA TURAL HISTOR Y OF SELBORNE. 



LETTER XXXV. 



TO THE SAME. 



SELBORNE, May 2oi7i, 1777. 



DEAR SIR, Lands that are subject to frequent inundations are 

 always poor ; and probably the reason may be because the worms 

 are drowned. The most insignificant insects and reptiles are of 

 much more consequence, and have much more influence in the 

 economy of Nature, than the incurious are aware of; and are 

 mighty in their effect, from their minuteness, which renders them 

 less an object of attention : and from their numbers and fecundity. 

 Earth-worms, though in appearance a small and despicable link in 

 the chain of Nature, yet, if lost, would make a lamentable chasm. 

 For to say nothing of half the birds, and some quadrupeds which 

 are almost entirely supported by them, worms seem to be the 

 great promoters of vegetation, which would proceed but lamely 

 without them, by boring, perforating, and loosening the soil, and 

 rendering it pervious to rains and the fibres of plants, by drawing 

 straws and stalks of leaves and twigs into it ; and, most of all, by 

 throwing up such infinite numbers of lumps of earth called worm- 

 casts, which, being their excrement, is a fine manure for grain and 

 grass. Worms probably provide new soil for hills and slopes where 

 the rain washes the earth away ; and they affect slopes, probably to 

 avoid being flooded.* Gardeners and farmers express their 

 detestation of worms ; the former because they render their walks 

 unsightly, and make them much work ; and the latter because, as 

 they think, worms eat their green corn. But these men would find 



* We rcarcely agree with White's proposition here ; grass lands are very much benefited 

 by frequent inundations. That worms are great fertilisers there can he no doubt, but at 

 the same time in all cases they are not beneficial, as for instance in fl jwer-pots or boxes 

 where plants are kept. In pasture lands, however, they do act mechanically, and their 

 castings or excrement (earth-worm guano), is often very abundant, so much so as to mark 

 the surface. Mr. Darwin applies the offices of worms geol igically by their gradually 

 covering the surface of land, and concealing loose stones, &c., which, however, may be 

 also assisted by the decomposition of vegetable matter; he goes so far as to say, " that 

 every particle of earth in old pasture land has passed through the intestines of wor ns, 

 and hence that in some instances, the term ' animal world ' would be more appropriate 

 than 'vegetable world.'" (Proceed. Geol. Soc.} It is remarkable after a flood has 

 covered the low pastures to observe the numbers of birds, crows, thrushes, herons, gulls, 

 that assemble when the water recedes ; the drowned earih-wjrm is their chief prey. 



