George Henry Lewes

“ You want to know what that dust is? It is always to be found in dry gutters on the housetops, or in dry moss growing on an old wall; and Spallanzani, the admirable naturalist to whom we owe so much, amazed the world with announcing what old Leeuwenhoek had before announced, namely, that these grains of dust, when moistened, suddenly exhibited themselves as highly-organised little animals—the Rotifers and Tardigrades. Water is necessary to their activity. When the gutter is dried up, they roll themselves into balls, and patiently await the next shower. ”

“ This persistent presence of starch on our hands is not astonishing when we consider the enormous amount of starch which must be rubbed from our food, and our linen, every instant of the day; and when we consider, on the one hand, the specific lightness of these grains, which enables them to be so easily transported by the air, and, on the other hand, the powerful resistance they offer to all the ordinary causes of destruction, one may safely affirm that in every town or village a cloud of starch is always in the air. ”

“ It is probable, however, that while you were perfectly familiar with the idea of the atmosphere carrying clouds of dust, on occasions, you never thought of the atmosphere being constantly loaded with dust, which is constantly being deposited, and constantly renewed. This sunbeam has made the fact visible. It has lighted up the tiny cloud of dust, which we see to be restlessly whirling. ”

“ There is one thing which will perhaps be found in every place, and in every pinch of dust, and you will be not a little surprised to learn what that is. It is starch. No object is more familiar to the microscopist than the grain of starch. It is sometimes oval, sometimes spherical, and varies in size. The addition of a little iodine gives it a blue colour, which disappears under the influence of light. There seems to be no difference between the starch grains found in the dust of Egyptian tombs and Roman temples, and that found in the breakfast-parlour of to-day. ”

“ It is true that unless your housemaid is a woman of stern conscientiousness, the mortal enemy of spiders, implacable on the subject of cleanliness— (a housemaid, in short, who never advertises in the “Times,” but is a tradition of the days that are gone) —you must on more than one occasion have found a layer of dust collected on your books, portfolio, or table, dust piled up in the corners of the picture frame, dust covering your microscope case, dust gathering in the carvings of the piano-forte legs, dust on the looking-glasses, dust on the windows, dust everywhere. ”

“ The silk is unwound, is carried to England or France, is there woven into a beautiful fabric, and after passing through many hands, enriching all, it forms part of the dress of some lovely woman, or the neck-tie of some gentlemanly scoundrel. Contact with a rough world, or a stiff shirt-collar, rubs off a minute fibre; the wind carries it away; and, after more wanderings than Ulysses, it comes to the stage of our Microscope. ”

“ Starch must necessarily abound, because the wheat, barley, rice, potatoes, &c., which form everywhere the staple of man’s food, are abundant in starch; the grains are rubbed off, and scattered by the winds in all directions. ”

“ 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. ”

“ But the great pathologist Virchow discovered that in various tissues a substance closely resembling starch was formed, which he considered to be a morbid product. The discovery made a great sensation, and many were the ingenious theories started to account for the fact. At last it came to be maintained that starch was a normal constituent of animal tissues; and there is no doubt that investigators might easily find starch in every bit of tissue they handled, since their fingers, as we have seen, are plentifully covered with grains. ”

“ 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. ”

“ So widely are these grains distributed that a careful examination of our clothes always detects them. Nay, they are constantly found on our hands, though unsuspected until their presence on the glass slide under the Microscope calls attention to them. It is only necessary to take a clean glass side, and press a moistened finger gently on its surface, to bring several starch grains into view. ”

“ There is evidence enough of the transporting power of the air, without falling into exaggerations. By slow deposits from the air the temples of Egypt, Greece, and Rome are now to a great extent buried below the surface; and you have often to descend a flight of steps to get upon the ancient soil. ”

“ It may happen that the wind will sweep them into your study, and there they will settle on the gilt edges of Rollin’s Ancient History, or some other classical work which every gentleman’s library should be without ”