The principles of descriptive and physiological botany / [J.S. Henslow].

  • John Stevens Henslow
Date:
1844
Catalogue details

Licence: Public Domain Mark

Credit: The principles of descriptive and physiological botany / [J.S. Henslow]. Source: Wellcome Collection.

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    indeed, there is no difficulty in pointing out numerous lines of demarcation between the two kingdoms; but, as we descend in the scale of each, we find an increasing similarity in external characters, and a closer approxi- mation between the analogies existing in many of those functions which mark the presence of the living principle, both in the animal and in the vegetable king- doms. Perhaps, until the contrary shall be distinctly proved, we may consider the superaddition of “ sen- sibility” to the living principle as the characteristic property of animals ; a quality by which the individual is rendered conscious of its existence or of its wants, and by which it is induced to seek to satisfy those wants by some act of volition. It has been supposed—and both analogy and experiment appear most fully to con- firm the supposition—that a sense of pain is very nearly, if not entirely, absent in the inferior tribes of animals. Even in the higher tribes, certain parts of the body are incapable of receiving pain; and there seems to be no absurdity in considering that an animal may be endowed with just so much sensibility as may be sufficient to prompt it toselect its food, though at the same time its body may be so organised as to be incapable of transmitting painful sensations. But the most constant, if not uni- versal, distinction, and one which we can readily appre- ciate, between animals and vegetables,—consists in the presence or absence of those internal sacs or stomachs, with which the former alone are provided, for receiving their food in its crude state, previously to its being elaborated by the organs of nutrition.
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