Principles Of General And Comparative Physiology

Excerpt from Principles of General and Comparative Physiology: Intended as an Introduction to the Study of Human Physiology, and as a Guide to the Philosophical Pursuit of Natural History It is a work which all hospital surgeons will possess - indeed, which all surgeons who wish to be well acquainted with their profession should.-dr. Johnson's Review. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1841 edition. Excerpt: ... between the veins of the system and the respiratory vessels, was seen in the Crustacea, where the venous sinuses, situated at the commencement of the branchial arches, may be regarded as so many repetitions of a simple form of a respiratory heart. In the class of Fishes, it will be seen that the heart is entirely respiratory, the arterial trunk which proceeds from it being distributed at once to the gills, and the blood which has been aerated in them being returned into a systemic artery or aorta, whence it proceeds to the body at large. In the higher Cephalopoda we observe a curious form of the circulating apparatus, which manifestly establishes the transition between that of the Mollusca in general, and that which is peculiar to Fishes. The systemic heart consists of only one cavity or ventricle, which is usually of a globular form, tolerably strong and muscular, and exhibiting bundles of fibres (carnece columtue) interlacing with one another (Fig. 118), as well as distinct valves protecting the mouths of the vessels which open into it. The aorta which proceeds from it, distributes arterial blood to the general system; and this is returned by means of the venous trunks, not immediately to the gills, as in the other Mollusca, but to two superadded impelling cavities, one of which is situated in connection with each row of gills. These branchial ventricles are less powerful than that which propels the blood through the system; but they are still sufficiently muscular and contractile to accelerate the circulation through the respiratory organs, and thus to prepare the blood for the maintenance of the increased muscular exertions which are required for the superior locomotive powers of these animals, as well as for the general activity of...