A lecture, introductory to a course of lectures, on anatomy, physiology, and surgery / delivered at the School of Medicine and Surgery, Gerrard Street, Soho, by G.D. Dermott.

  • Dermott, G. D. (George Darby), 1802-1847.
Date:
1833
Catalogue details

Licence: Public Domain Mark

Credit: A lecture, introductory to a course of lectures, on anatomy, physiology, and surgery / delivered at the School of Medicine and Surgery, Gerrard Street, Soho, by G.D. Dermott. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    D circulation of the sap ; the digestion or creation of the sap in. the root; the respiration of the leaves ; tlie various secretions of a plant, including the deposition or accretion of fresh substance from the sap producing growth, are all living actions of the Plant. To say that the vessels of a Plant have not a living agency (in ad- dition to the slight assistance which may be afforded to the circu- lation by capillary attraction) is as inconsistant as to deny to any other living structure a living function ; Life is here the go- verning agent, capillary attraction the subsidiary. Yet these vessels are not known to have vasa vasorum. Nay, I will go still further, and say that I think the vessels of Plants must have some elementary nervous substance, something analogous to a Sympathe- ticus Maximus, which makes them sensible to their stimuli; may not this be depending upon the presence of nervous substance (or granula) in its simplest state, without perception, and without any modification of a brain ?—nay, we may even go further still, and say, that if muscular fibre exists where action exists, and if action exists where muscular fibre exists, why then we must have a modification of muscular fibre existing, not only in Polypi, but even in the sensitive Plant. Now I have stated that the Blood is the primary magazine of Vitality—but that 2ndly a part may be alive without possessing vessels. These two positions may appear paradoxical, but they are not so. The J^ital principle I believe to he an invisible material sub- stance existing in the Blood, and by its peculiar stimulus, stimu- lating the Arteries into action, and thus Life as it were dcvelopes itself, which action of the Arteries may be a means of secreting it or throwing it out from the Blood,whereby it becomes developed by its effects or properties in different structures; besides this princi- ple being separated from the Blood by the living agency of the ex- tremities of Arteries, I believe that this principle like heat, per- ineates through living structure, and is communicable from one living substance to another. This must be the case, or the coats of the minutest vasa vasoram could not possess Vitality ; but the sub- stance to receive Vitality must be in a state of predisposition to do so, and nmst I think be in contact with the substance from which it is to receive it. For instance coagulable lymph separated from the Blood and no longer in contact with the living surface which produces it, or with any other living surface, coagulates—and this coagulation is an action of life, but is the dying action of the lymph. On the con- trary, keep this coagulable lymph in contact with the living sur- face, and it not only coagulates, but continuing to have commu- nicated to it a supply of Vitality from the producing surface— vessels are created in the coagulum, by the act of Vitality within it—then this coagulum beginning to have a vehicle of vitality of