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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    MRS. B. Not precisely in the same manner that we’clo; but air is so essential an agents both chemically and mecha- nically, in promoting their nourisliment and growth, that it is scarcely less necessary to their existence than to that of animals. Indeed, it is the opinion of M. de Candolle, that the function of transmitting air is not confined to the trachete, but extends throughout the vascular system. The whole of the vegetable kingdom consists of masses of these several elementary organs, with the ex- ception of fungi, mosses, and lichens, whose vessels are all of a cellular form, without any vascular system whatever. ICMILV. That affords a strong argument against the passage of the sap through the vascular system. MRS. B. Certainly. The fibres of plants are composed of collections of these vessels and cells closely connected together. The root and stem of plants consist of such fibres ; if you attempt to cut them transversely, you meet with considerable resistance, as you must force your way across the tubes, and break them ; whilst, if you slit the wood longitudinally, you separate the ves- sels without breaking them, and have only to force your way through the elongated cellular tissue which con- nects them. EMIUY. . d’hc difference is very observable : hut I wonder ‘Ifat the cells, being formed of a delicate membrane, arc not squeezed and crushed to pieces in the stems of plants, especially when they become hard w'ood. MRS. B. The cells, by the growth of the stem, are frequently