Th’ invisible in things scarce seen revealed;
To whom an atom is an ample field.”
Animalcules in general, continues Mr. Adams, are observed to move in all directions with equal ease and rapidity, sometimes obliquely, sometimes straight forward; sometimes moving in a circular direction, or rolling upon one another, running backwards and forwards through the whole extent of the drop, as if diverting themselves; at other times greedily attacking the little parcels of matter they meet with. Notwithstanding their extreme minuteness, they know how to avoid obstacles, or to prevent any interference with one another in their motions: sometimes they will suddenly change the direction in which they move, and take an opposite one; and, by inclining the glass on which the drop of water is, as it can be made to move in any direction, so the animalcules appear to move as easily against the stream as with it. When the water begins to evaporate, they flock towards the place where the fluid is, and show a great anxiety and uncommon agitation of the organs with which they draw in the water. These motions grow languid as the water fails, and at last cease altogether, without a possibility of renewal if they be left dry for a short time. They sustain a great degree of cold as well as insects, and will perish in much the same degree of heat that destroys insects. Some animalcules are produced in water at the freezing point, and some insects live in snow.
[In the American Journal of Science and Arts for April, 1830, there is a letter to the editor, from Dr. Joseph E. Muse, from which the following is an extract:
“When the winter had made considerable progress, without much frost, there happened a heavy fall of snow; apprehending that I might not have an opportunity of filling my ice house with ice, I threw in snow, perhaps enough to fill it; there was afterwards severely cold weather, and I filled the remainder with ice; about August the waste and consumption of ice, brought us down to the snow; when it was discovered that a glass of water which was cooled with it, contained hundreds of animalcules, I then examined another glass of water, out of the same pitcher, and with the aid of a microscope, before the snow was put in it, found it perfectly clear and pure; the snow was then thrown into it, and on solution the water again exhibited the same phenomenon; hundreds of animalcules, visible to the naked eye with acute attention, and when viewed through the microscope resembling most diminutive shrimps; and wholly unlike the eels discovered in the acetous acid, were seen in the full enjoyment of animated nature.
“I caused holes to be dug in several parts of the mass of snow in the ice house, and to the centre of it; and in the most unequivocal and repeated experiments had similar results.”]
There is one remarkable circumstance, says Mr. Lobb, that we must not pass over in our contemplation of these minute animals: which is, that they are found proportionably much stronger, more active and vivacious, than large ones. The spring of a flea in its first leap, how vastly does it outstrip any thing of which animals are capable! A mite, how vastly swifter does it run than a racehorse! M. de L’Isle has given the computation of the velocity of a little creature scarcely visible by its smallness, which he found to run three inches in half a second: now, supposing its feet to be the fiftieth part of a line, it must make 500 steps in the space of three inches; that is, it must shift its legs 500 times in a second, or in the ordinary pulsation of an artery!
The modes of propagation among these animalcules are various, and the observation of them is extremely curious. Some multiply by a transverse division; and it is remarkable, that though in general they avoid one another, it is not uncommon, when one is nearly divided, to see another push itself upon the small neck which joins the two bodies in order to accelerate the separation. Others, when about to multiply, fix themselves to the bottom of the water; then becoming first oblong, and afterwards round, turn rapidly as on a centre, but perpetually varying the direction of their rotatory motion. In a little time, two lines forming a cross are perceived: after which the spherule divides into four, which grow, and are again divided as before.[148] A third kind multiply by a longitudinal division, which in some begins in the fore part, in others in the hind part; and from others a small fragment detaches itself, which in a short time assumes the shape of the parent animalcule. Lastly, others propagate in the same manner as the more perfect animals.
The same rule seems to hold good in these minute creatures, which is observable in the larger animals, namely, that the larger kinds are less numerous than such as are smaller, while the smallest of all are found in such multitudes, that there seem to be myriads for one of the others. They increase in size, like other animals, from their birth, till they have attained their full growth: and when deprived of proper nourishment, they in like manner grow thin and perish.
And, if the extreme minuteness of the parts of animalcules is not merely surprising, but far above our utmost conception, what shall we say to those various species, to which the mite itself, in point of size, is, as it were, an elephant? Naturalists suppose another species, or order, of invisible animalcules; namely, such as escape the cognizance even of the best microscopes, and give many probable conjectures concerning them. Reason and analogy give some support to the existence of an infinite number of these imperceptible creatures. The naked eye, say some, takes in from the Elephant to the Mite; but there commences a new order, reserved only for the microscope, which comprehends all these from the Mite to those twenty-seven millions of times smaller; and this order cannot be said to be exhausted, if the microscope be not arrived at its last degree of perfection.
Among the Egyptians, all the natives of the water were in some degree esteemed sacred. In many parts the people did not feed upon them. The priests in particular never tasted this kind of food; and the reason why they abstained from it, was the sanctity imputed to this class of creatures. For they were sometimes considered as sacred emblems: at other times worshipped as real deities. One species of fish called Oxurunchus, had, according to Strabo, a temple, and divine honors paid to it. A fish called Phagrus, was, according to Clemens Alexandrinus, worshipped at Syene. The Lepidotus and Eel, were, as we find from Herodotus, objects of adoration; being each, sacred to the god Nilus. This is ridiculed by Antiphanes, who says, that an Eel among the Egyptians was reverenced equally with their gods.