202 NATURAL HISTORY 



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. Gar- 

 deners 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 

 that the earth without worms would soon become cold, hard- 

 bound, and void of fermentation ; and consequently steril : 

 and besides, in favour of worms, it should be hinted that 

 green corn, plants, and flowers, are not so much injured by 

 them as by many species of coleoptera (scarabs), and tipulce, 

 (long-legs) in their larva, or grub-state ; and by unnoticed 

 myriads of small shell-less snails, called slugs, which silently 

 and imperceptibly make amazing havock in the field and 

 garden. 4 



These hints we think proper to throw out in order to set 

 the inquisitive and discerning to work*. 



A good monography of worms would afford much enter- 

 tainment and information at the same time, and would open 

 a large and new field in natural history. Worms work most 



i Farmer Young, of Norton-farm, says that this spring (1777) about 

 four acres of his wheat in one field was entirely destroyed by slugs, which 

 swarmed on the blades of corn, and devoured it as fast as it sprang. 



* [The important functions performed by earthworms so sensibly 

 suggested in the text formed the subject of an elaborate and interesting 

 paper by Mr. Darwin, which was published in the Transactions of the 

 Geological Society (ser. 2, vol. v. p. 505), in which he shows that these de- 

 spised creatures are instrumental in comminuting the soil, and producing a 

 superficial bed above the previous surface, and forming a layer of mould 

 perfectly prepared for vegetable growth. The rate at which this layer 

 of new soil is formed may be guessed at from some of the facts stated 

 by Mr. Darwin. In one case, in a field which had been reclaimed from 

 waste land, 3 inches depth of mould had been prepared by the worms in 

 15 years; and in another, within a period of less than 80 years, the 

 earthworms covered the marl with a bed of earth of no less than 12 or 

 13 inches. T. B.] 



