The philosophy of natural history / by William Smellie ; with an introduction and various additions and alterations intended to adapt it to the present state of knowledge by John Ware.

  • Smellie, William, 1740-1795.
Date:
1827
Catalogue details

Licence: Public Domain Mark

Credit: The philosophy of natural history / by William Smellie ; with an introduction and various additions and alterations intended to adapt it to the present state of knowledge by John Ware. Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

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    horns of animals; the trunks, branches, and roots of trees retain, for an almost indefinite length of time, under certain circum- stances, their shape and substance. This, however, is owing not to their continuing to possess life itself, but to the particular nature and composition of the texture of which they are com- posed. Nothing like this takes place in other substances ; they can be destroyed only by the action of some mechanical agent, which separates their parts, or by that of some chemical one, which alters their combinations. These are circumstances of distinction common to all living bodies, whether animal or vegetable. But another subject of inquiry is, how are these to be distinguished from each other ? Although it may seem very easy to distinguish an animal from a vegetable, yet the true principle of distinction eludes investiga- tion. Many philosophers have attempted to define wherein it consists, but have failed in the attempt. There is generally little practical difficulty in determining whether any particular substance belong to the animal or vegetable kingdom, and yet so nearly do the lower species of animals resemble plants in the functions they perform, that it is almost impossible to point out what constitutes the real difference between them. Some writers, among whom was the celebrated Buffon, have believed that there is in fact no exact boundary between the animal and vegetable kingdoms, that they run into each other at their extremities, and form so regular a gradation from the one to the other, thai no precise dividing line can be drawn between them. But although there is this apparent confusion at the boundaries of the two kingdoms, yet, generally speaking, animals are distinguished from plants by their composition, their structure, their mode of life, he. And although with respect to each par- ticular circumstance there may be particular exceptions, yet, taking the whole together, we get a good general idea of an animal as distinguished from a plant. Thus the power of loco- motion, or of motion from place to place, has been considered as peculiar to animals, and in a general way it is so; yet there are many exceptions. Oysters, the sea anemone, corals, and coral- lines, now known to be of an animal nature, can hardly be said to enjoy the power of local motion. Many species remain fixed to the rocks on which they were produced, and have no motion but that of extending and contracting their bodies. And, on the other hand, some species of plants are not fixed by roots to one and the same spot, but float about in the sea, receiving nourishment from its waters.