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THE FORMATION OF VEGETABLE MOULD THROUGH THE ACTION OF WORMS, WITH OBSERVATIONS ON THEIR HABITS. By Chas. Darwin, LL.D., F.R.S. With Illustrations. London: John Murray.

Mr Darwin's new monograph, the fruit of observations extending over half a century, ought to make mankind look with more respect on the worm. Its place in the economy of nature is shown to be vastly more important than we had any idea of. Its labours form the upper layer of rich mould which alone man employs in his agricultural operations. Archæologists have the worm to thank for the preservation of coins, gold ornaments, stone implements, and other objects dropped upon the surface of the soil. It is even by the agency of the worm more than aught else that Roman villas and towns have been buried and preserved. Finally, the worm is a geological agent of vast importance, the denudation and sculpture of the earth's surface being largely due to its actions. We are assisted to the acceptance of these marvellous conclusions by the ascertained fact that the castings of the worm amount of the average to a uniform layer of mould one-fifth of an inch thick every year. In many parts of England a weight of more than ten tons of dry earth annually passes through their bodies and is brought to the surface on each acre of land. The despised worm, is, in fact, the most potent of all gardeners. It prepares the ground in a most excellent manner for the growth of fibrous-rooted plants and for seedlings of all kinds, sifting the soil and mingling its constituents intimately together, like a gardener who prepares fine mould for his choicest plants. The worm, besides being a gardener, is also a great ploughman; and it is a marvellous reflection that the whole of the superficial mould over any wide, turf-covered expanse has passed and will again pass, every few years, through the bodies of worms. "It may be doubted," says Mr Darwin "whether there are many other animals which have played so important a part in the history of the world as have these lowly organised creatures. [Earthworms, p. 313]

Mr Darwin's observations and experiments prove that the earthworm has no eyes, and yet is sensitive to light, retreating rapidly into its holes when brightly illuminated; that while it can live for many weeks under water it is destroyed by the dry atmosphere of a room even in one night; that though deaf, it possesses the power of attention, and is sensitive to heat and cold; that it has but a feeble power of smell, considerable acuteness in taste, and a highly developed sense of touch, which is almost uniformly active in every part of the body. What has surprised Mr Darwin more than anything else in regard to worms is the degree of intelligence exhibited in the plugging up of the mouths of their burrows with various objects. This seems their strongest instinct, and it is developed even in very young worms. Though they can feed on earth alone, extracting nutriment from the organic matter contained in it, they are very fond of eating succulent vegetables (especially celery), fat, raw meat, and even their dead comrades. It is shown, as a new fact of great physiological interest, that the earthworm ejects from its mouth on to leaves a fluid which partially digests them before it proceeds to nibble and swallow the softened fragments. Mr Darwin's new monograph will deepen the sense of his marvellous patience as a minute observer of nature, in which respect he can hardly be said to have any equal.