Conversations on vegetable physiology ; comprehending the elements of botany, with their application to agriculture / Mrs. Marcet.

  • Marcet, Mrs. (Jane Haldimand), 1769-1858.
Date:
1839
Catalogue details

Licence: Public Domain Mark

Credit: Conversations on vegetable physiology ; comprehending the elements of botany, with their application to agriculture / Mrs. Marcet. Source: Wellcome Collection.

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    4S medium I have mentioned, it was observed that the sap naturally ascended in straight lines, but that, if it en- countered any obstacle, it could move obliquely, or even spread itself laterally. A great variety of experiments have been made in order to ascertain the degree of velocity with which the sap rises; but as the rapidity of its ascension depends in a great measure upon the means which the plant has of parting with it by exhalation, we cannot well follow its progress, without having previously made acquaint- ance with the excretory organs of plants — the leaves, whose office it is to exhale that portion of the sap which is superfluous. OAnOLlNE. The whole of the sap, then, is not required for the nourishment of the plant ? MRS. B. That nourishment is a more complicated operation than you are aware of: all the water which enters into the plant is not retained by it; part of it passes through the leaves into the atmosphere, and the atmosphere, in its turn, contributes to the nourishment of the plant. But we must not anticipate; and, at our next interview, we will examine the structure and agency of the leaves of plants.