Bionomia : opinions concerning life and health introductory to a course of lectures on the physiology of sentient beings ... / By A.P. Buchan.

  • Buchan, A. P. (Alexander Peter), 1764-1824.
Date:
1811
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Licence: Public Domain Mark

Credit: Bionomia : opinions concerning life and health introductory to a course of lectures on the physiology of sentient beings ... / By A.P. Buchan. Source: Wellcome Collection.

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    changes are not inseparably conjoined, with their effects, as in the case of physical causation; nor are they connected through the medium of volition, as actions are with motives; but, their influence varying in relation to the state of the vital principle, they may be distinguished by the appellation of occasional, or exciting causes. 32. The peculiar nature and the limits of this class of causes, are aptly illustrated by the phenomena, which occur during the develope- merit of the embryo animal or plant. If a recent egg be exposed to a certain degree of warmth, or a ripe acorn to a proper share of heat and moisture, a young animal or plant will in due time be evolved. But if the seed or the egg has been previously deprived of the princi- ple of life, or the degree of heat to which either is exposed, exceed certain limits, results of a very different kind will be the consequence.* * Philosophical Essays by Dr. J. Gregory. c