The natural history of animalcules

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Page 18 - ... peculiar constructions: thus, for instance, while some move through the water with the greatest imaginable rapidity, darting, leaping, or swimming, others merely creep or glide along ; and many are altogether so passive that it requires long and patient observation to discover any of their movements at all. One description are perceptibly soft, and yield easily to the touch ; another are covered with a delicate shell or horn-like coat. Of the latter order there are different degrees of density,...
Page 13 - Until the introduction of vegetable colouring matter into the fluid, which supplies them with food, — an experiment that has been attended with very successful results, — these creatures were commonly supposed to be entirely devoid of internal organization, and to be nourished by the simple process of cuticular absorption. By the application of coloured substances, which, moreover, have been found to invigorate rather than to depress the animalcule, and to...
Page 13 - ... successful results, — these creatures were commonly supposed to be entirely devoid of internal organization, and to be nourished by the simple process of cuticular absorption. By the application of coloured substances, which, moreover, have been found to invigorate rather than to depress the animalcule, and to maintain it in the full exercise of all its functions, this erroneous notion is set at rest, and an internal structure is discerned in some, equal, if not surpassing that of many of the...
Page 17 - Vorticella, and, lastly, the Brachioni ; and thus a single infusion will repay for the little trouble of making it, with a great variety of species. Water in which flour has been steeped will be found to abound also with animalcules : and it is remarked by G. Leach, Esq. that the leaden troughs, constantly appropriated for birds to drink out of, contain several descriptions of them, and more especially those of the wheel genus. In ponds, too, especially in the shallow parts, near their edges, and...
Page 19 - ... and incloses the creature, like that of the oyster or muscle." "All vertebrated animals are either oviparous or viviparous, which terms sufficiently designate their modes of production : but it is not so with animalcules ; for, in addition to these two methods — 1. Animalcules propagate by a spontaneous scissure, or division of their bodies into two or more portions, each one forming a new creature, which, on its arrival at maturity, pursues the same course. These divisions take place in some...
Page 12 - ... fluids, which are too minute to be scanned, or even seen by the naked eye ; such, for instance, as those produced in inconceivable numbers from infusions of animal and vegetable matter.
Page 16 - ... quinine in them, or the intention will be frustrated. Immerse these, whatever they may be, for a few days, in some clear water, when, if the vessels which contain them be not agitated, a thin pellicle or film will be discerned on the surface, which, under the microscope, will be seen to be inhabited by several descriptions of animalcules : the first produce are commonly those of the simplest kind, such as the Monads. In a few days more, their numbers will increase to such an amazing extent, that...
Page 26 - ... or sacs themselves are only to be observed when the animalcule is fed with particles of colouring matter ; the food on which they mainly exist being as pellucid as themselves; the cavities are invisible. They increase by a spontaneous division of the parent into two or more parts, and those parts or young again divide when they have attained their full size. As subjects of observation, they are principally interesting from their minuteness, being, as they are, the very limit of man's acquaintance...
Page 11 - ... by plates, lately published by Mr. Prichard, called the Natural History of Animalcules. ' The bare knowledge that there are myriads of atoms existing in a single drop of water, recreating and executing all their functions and evolutions with as much rapidity and apparent facility as if the range afforded to them was as boundless as the ocean, must carry with it an intensity of interest to the mind of every human being ; of every one, at least, who is at all accustomed to meditate on the perfections...

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