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Handbook of Nature-Study 



THE EARTHWORM 



Teacher's Story 



LTHOUGH not generally considered attractive, 

 for two reasons the earthworm has an impor- 

 tant place in nature-study: it furnishes an 

 interesting example of lowly organized crea- 

 tures, and it is of great economic importance 

 to the agriculturist. The lesson should have 

 special reference to the work done by earth- 

 worms and to the simplicity of the tools with 

 which the work is done. 



The earthworm is, among lower animals, 

 essentially the farmer. Long before man con- 

 ceived the idea of tilling the soil, this seemingly 

 insignificant creature was busily at work 

 plowing, harrowing, and fertilizing the land. Nor did it overlook 

 the importance of drainage and the addition of amendments — 

 factors of comparatively recent development in the management of the 

 soil by man. 



Down into the depths, sometimes as far as seven or eight feet, but 

 usually from twelve to eighteen inches, goes the little plowman, bringing 

 to the surface the subsoil, which is exactly what we do when we plow 

 deeply. To break up the soil as our harrows do, the earthworm grinds it 

 in a gizzard stocked with grains of sand or fine gravel, which act as mill- 

 stones. Thus it turns out soil of much finer texture than we, by harrow- 

 ing or raking, can produce. In its stomach it adds the lime amendment, 

 so much used by the modern farmer. The earthworm is apparently an 

 adept in the use of fertilizers ; it even shows discrimination in keeping the 

 organic matter near the surface, where it may be incorporated into the 

 soil of the root zone. It drags into its burrows dead leaves, flowers and 

 grasses, with which to line the upper part. Bones of dead animals, shells, 

 and twigs are buried by it, and, being more or less decayed, furnish food 

 for plants. These minute agriculturists have never studied any system 

 of drainage, but they bore holes to some depth which carry oiT the surplus 

 water. They plant seeds by covering those that lie on the ground with 

 soil from below the surface — good, enriched, well granulated soil it is, too. 

 They further care for the growing plants by cultivating, that is keeping 

 fine and granular, the soil about the roots. 



It was estimated by Darwin that, in garden soil in England, there are 

 more than 50,000 earthworms in an acre, and that the whole superficial 

 layer of vegetable mold passes through their bodies in the course of every 

 few years, at the rate of eighteen tons per acre yearly. 



This agricultural work of the earthworm has been going on for ages. 

 Wild land owes much of its beauty to this diminutive creature which 

 keeps the soil in good condition. The earthworm has undermined and 

 buried rocks, changing greatly the aspect of the landscape. It has 

 preserved ruins and ancient works of art. Several Roman villas in 

 England owe their preservation to the earthworm. All this work is 

 accomplished with the most primitive tools, a tiny proboscis, a distensible 

 pharynx, a rather indeterminate tail, a gizzard and the calcareous glands 

 peculiar to this lowly creature. 



