Inaugural dissertation on the nature of respiration, and the extent of its connection with the nervous system : sumitted to the Medical Faculty of the University of Edinburgh, in conformity with the rules for graduation, by authority of the Very Rev. Principal Baird, and with the sanction of the Senatus Academicus / by George A.F. Wilks.

  • Wilks, George Augustus Frederick.
Date:
1835
Catalogue details

Licence: Public Domain Mark

Credit: Inaugural dissertation on the nature of respiration, and the extent of its connection with the nervous system : sumitted to the Medical Faculty of the University of Edinburgh, in conformity with the rules for graduation, by authority of the Very Rev. Principal Baird, and with the sanction of the Senatus Academicus / by George A.F. Wilks. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    experiment be reversed, and the tail only of the fish be re- moved from the water, the head and gills remaining im- mersed, the fish continues to live and to increase in weight, but the tail becomes dry on the surface, shewing that the fluid thus absorbed was not distributed to the tail in a proportion sufficient to repair the loss sustained by perspi- ration in air.* The respiration of fishes when removed from aerated into non-aerated water, is influenced in a re- markable degree by the temperature of the medium. A fish immersed in water, deprived of air at 32°, will live much longer than the same fish immersed in the same fluid at 104°. Scarcely any fish will live more than two minutes in water of 104° deprived of air. The period to which life may be prolonged in non-aerated water at low temperatures, varies with the species. The same effect of temperature is observed in a limited quantity of aerated water.-f- The respiratory apparatus in fishes consists of thin leaf- lets or laminae, over which innumerable vessels are distri- buted, and which are attached to arches connected with the OS hyoides. The water is swallowed by the fish, and escapes between these laminae by apertures for that purpose. The blood is propelled into the gills by a fleshy heart, which represents the right auricle and ventricle of warm-blooded animals. Cartilaginous fishes have, many of them, the gills fixed on the outer edge, and present as many external apertures for the escape of the water as there are interspaces between them. The lamprey, the ray, and the shark, have * A somewhat different explanation of these phenomena as exhibited in fishes, has been attempted by Flourens ; he endeavours to ascribe the cessa- tion of the action of the gills, to the loss of the momentum of the water, in unfolding and expanding the branchial filaments, rather than to any loss of power in the muscles occasioned by their exsiccation. ■j- The smallest quantity of oxygen which has been known to support the life of a fish for any considerable period, is l-5000th of the bulk of the fluid ; the usual average in river water is one per cent.'—£du'ards.