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14, 1860.] from thence to Constantinople; and, after being shaken from the robe of Theodora, or the code of Justinian, it might have accompanied the Crusaders to Jerusalem; from which place Mrs. Brown, after a two months’ Eastern scamper, might have brought it back to London, where a chance breeze wafted it into the room which the very sunbeam I am discoursing about illuminates. From Memphis to my Microscope, what a course! And during this adventurous course our Rotifer has fourteen times shaken off the cerements of death. Dead? Not he:

Such are some of the things found in the dust of a sunbeam, and you will probably have been too much astonished at some of the facts to have made the reflection that among all these objects not a single egg has been named. A few spores of plants are, indeed, frequently found. Knowing that many plants are fertilised by the agency of the wind, one expects to find pollen grains abundant. Indeed, when we consider how rapidly bread, cheese, jam, ink, and the very walls of the room, if damp, are covered with mould, which is a plant; when we consider how impossible it is to keep decaying organic substance free from plants and animalcules, which start into existence as by magic, and in millions, we have no difficulty in accepting the hypothesis of an universal diffusion of germs—eggs or seeds—through the atmosphere. No matter where you place organic substance in decay, if the air in never so small a quantity can get at it, mould and animalcules will be produced. Close it in a phial, seal the cork down, take every precaution against admitting more air than is contained between the cork and the surface of the water; and although you may have ascertained that no plants or animalcules, no seeds or eggs, were present when you corked the bottle, in the course of a little while, say three weeks, on opening the bottle you will find it abundantly peopled.

To explain this, and numerous other facts, the hypothesis of an universal diffusion of germs through the air has been adopted; and the known fecundity of plants and animalcules suffices to warrant the belief that millions of millions of germs may be constantly floating through the air. Ehrenberg computes the rate of possible increase of a single infusory, Paramecium, at two hundred and sixty eight millions a month. And it is calculated that the plant named Bovista giganteum will produce four thousand million of cells in one hour. As the mould plants are single cells, and as they multiply by spontaneous division, the rapidity with which they multiply is incalculable.

From all this you see how naturally the idea of universal diffusion of germs has become an accepted fact. If it is a fact, we must feel not a little astonished at finding the dust we examine so very abundant in starch, coal, silica, chalk, rust, hair, scales, and even live animals, and so strangely deficient in this germ-dust! The germs are said to be everywhere: millions upon millions must be diffused through tho air; every inch of surface must be crowded with them. Do we find them?

We find occasional pollen grains and seeds. But we find no animalcule eggs, and no animals, except the Rotifers and Tardigrades. We find almost everything but eggs. “Oh!” you will perhaps remark, “that is by no means surprising; if they are diffused in such enormous quantities through the air, it stands to reason that they must be excessively minute, otherwise they would darken the air; and if they are excessively minute, they escape your detective Microscope—that’s all.” Your remark has great plausibility; indeed, it would have overwhelming force, were there not one fatal objection to the assumption on which it proceeds. If the eggs of animalcules were so excessively minute, as you imagine them to be, there would be no chance of our detecting them. But it happens that the size of the eggs of those animalcules which are known (and of many we are utterly ignorant) is, comparatively speaking, considerable; at any rate, the eggs, both from size and aspect, are perfectly recognisable inside the animalcule; and if we can distinguish these eggs when the parent is before us, or when we have crushed them out of her body, it will be difficult to suppose that we could not distinguish them among the other objects in a pinch of dust, when a drop of water has been added.

It will be seen from these remarks that I do not believe in the hypothesis of universal diffusion of germs through the air. I believe that almost all the eggs of animalcules are too easily destroyed to resist desiccation; and that in the air they would become dust and cease to be eggs. At any rate we find no trace of eggs in the air.

The dust which our sunbeam has lighted up is a various and varying cloud of inorganic and organic matters—a symbol of the wear and tear of life—a token of the incessant silent destruction to which the hardest or the most fragile substances are exposed. The sunbeam has not only lighted up that, but many other obscurities, and shown us in what a world of mystery we move. L.

, 32; Julia Kavanagh, 35; Matthew Arnold, 35; Florence Nightingale, 36; Rev. C. Kingsley, 40; Captain Mayne Reid, 41; G. H. Lewes, 42; Tom Taylor, 42; Shirley Brooks, 43; Albert Smith, 43; William Howard Russell, 43; Professor Aytoun, 46; R. Browning, 47; C. Mackay, 47; C. Dickens, 47; W. M. Thackeray, 48; A. Tennyson, 49; Fanny Kemble, 49; Sir Archibald Alison, 49; Mark Lemon, 50; Edward Miall, 50; R. M. Milnes, 50; W. E. Gladstone, 50; Hon. Mrs. Norton, 51; Charles Lever, 53; Professor Maurice, 54; Sir E. Bulwer Lytton, 54; Benjamin Disraeli, 54; Harrison Ainsworth, 54; Mary Howitt, 55; H. Martineau, 57; Mrs. Gore, 59; S. C. Hall, 59; Mrs. Marsh, 60; Barry Cornwall, 60; Samuel Lover, 61; Albany Fonblanque, 62; Rev. G. R. Gleig, 63; T. Carlyle, 64; W. Howitt, 64; Sir John Bowring, 67; Rev. H. H. Milman, 68; J. P. Collier, 70; Frances Trollope, 72; W. J. Fox, 73; Sir W. Napier, 74; Rev. Dr. Croly, 74; Lord Brougham, 81; and Walter Savage LandorLandor, [sic] 84.