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known to the world ; a remarkable illustration of this may be found in the publication 

 of Mr. Darwin's last work, "Vegetable Mold and Earth Worms." Notwithstanding the 

 vast amount of original investigation, of the utmost importance, on other scientific subjects 

 undertaken by this gentleman, the fruits of which have from time to time appeared in 

 his invaluable works, ever since 1837, when he read a paper on "The Formation of 

 Mold," to the Geological Society of London, he has been accumulating facts and making 

 observations, the results of which are set forth in this fascinating work. Some of the 

 experiments are most remarkable, and the care and patience exhibited by this great 

 worker in carrying them out, are very characteristic of the man ; and are so graphically 

 narrated that one who reads the book can almost fancy he has seen them performed. The 

 modifications of the earth's surface by the agency of these small creatures is so great as 

 to be almost incredible, were they vouched for by a less accurate experimentalist than 

 Dr. Darwin. As the result of various careful observations he found that, on one acre of 

 old pasture ground no less than fifteen tons of earth are annually swallowed by worms 

 below the surface, and thrown up above it in the shape of castings. 



He points out, too, that the burial of ancient Roman and other remains, scattered 

 over the country, in England, is due to worms, which keep continually throwing up the 

 soil from underneath them, and so let them sink. 



Among the insects which do actual good, those which perform the office of scavengers 

 are entitled to more than a passing consideration. These useful insects will be found 

 almost entirely among the Coleoptera or beetles, and the Diptera or flies. As Kirby and 

 Spence's valuable wwk, " Introduction to Entomology," is not easily attainable in this 

 country, I cannot do better than insert what they have written so well on this subject : — 

 " All substances must be regarded as nuisances and deformities, when considered with 

 relation to the whole, which are deprived of the principle of animation. In this relation 

 stand a dead carcase, a dead tree, or a mass of excrement, which are clearly encum- 

 brances that it is desirable to have removed, and the office of efiecting this removal is 

 chiefly assigned to insects, which have justly been called the great scavengers of nature." 



" How disgusting to the eye, how ofi'ensive to the smell, would be the whole face of 

 nature were the vast quantities of excrement, daily falling to the earth from the various 

 animals which inhabit it, suffered to remain until gradually dissolved by the rain, or 

 decomposed by the elements ! That it does not thus offend us, we are indebted to an 

 inconceivable host of insects, which attack it the moment it falls ; some immediately 

 begin to devour it, others depositing in it eggs from which are soon hatched larvae that 

 concur in the same office with ten-fold voracity ; and thus every particle of dung, at least 

 of the most offensive kinds, speedily swarms with inhabitants which consume all the 

 liquid and noisome particles, leaving nothing but the undigested remains, that soon dry, 

 and are scattered by the winds, while the grass upon which it rested, no longer smothered 

 by an impenetrable mass, springs up with increased vigour." Many of the Scarabseidae 

 or Diggers not only live on this tilthy material, but dig galleries below the mass into the 

 soil and carry down portions of it, to be food for the young larvae ; the benefit thus con- 

 ferred is two-fold : not only is the nuisance removed, but a fertilizer is carried down into 

 the soil, and canals are opened by which more may find its way in the same direction, 

 whenever rain falls. The beetles living in dung inhabit it in their perfect as well as larval 

 states ; and it is a curious fact, but they are very seldom found to have any of it adhering 

 to them. 



" Of the diptera, the larvae alone derive their nutriment from this source ; the imago, 

 which would be suff'ocated did it attempt to burrow into a material so soft, only lays its 

 eggs in the mass. The members of this order, too, are more select in their choice than 

 the coleoptera — not indeed as to delicacy — but they do not indiscriminately oviposit in 

 all kinds, some preferring horse-dung, others cow-dung, and others that of birds, etc. 



" Still more would our olfactory nerves be offended, and our health liable to fatal 

 injuries, if the wisdom and goodness of Providence had not provided for the removal of 

 another nuisance from our globe — the dead carcasses of animals. When these begin to 

 grow putrid, everyone knows what dreadful miasmata exhale from them, and taint the 

 air we breathe. But no sooner does life depart from the body of any creature than 

 myriads of differe nt sorts of insects attack it in various ways. First come the Histers, 



