Volume 1

A text-book of human physiology : including histology and microscopical anatomy : with special reference to the requirements of practical medicine / by L. Landois ; translated from the seventh German edition, with additions, by William Stirling.

Date:
1891
Catalogue details

Licence: Public Domain Mark

Credit: A text-book of human physiology : including histology and microscopical anatomy : with special reference to the requirements of practical medicine / by L. Landois ; translated from the seventh German edition, with additions, by William Stirling. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    Physiology of the Blood. ♦ [The blood is aptly described by Claude Bernard as an internal medium which acts as a “ go-between ” or medium of exchange for the outer world and the tissues. Into it are poured those substances Avliich have been subjected to the action of the digestive fluids, and m the lungs or other respiratory organs it receives oxygen. It thus contains new substances, but in its passage through the tissues it gives up some of these neAV substances, and receives m exchange certain waste products Avhich have to be got rid of. Its composition is thus highly complex. Besides carrying the new nutrient fluids to the tissues, it is also the great oxygen-carrier, as Avell as the medium by which some of the waste products, e.g., CO2, urea, are removed from the tissues, and brought to the organs, e.g., the lungs, kidneys, skin, Avliich eliminate them from the body. It is at once a great pabidum-supplying medium and a channel for getting rid of useless materials. As the composition of the organs through Avhich the blood flows va^ries, it is evident that its composition must vary in different parts of the circulatory system; and it also varies in the same indi\ddual under different conditions. StiU with slight variations, there are certain general physical, histological, and chemical properties Avhich characterise blood as a iohole.~\ 1. PHYSICAL PEOPERTIES.—(1) Colour. —The colour of blood varies from a bright scarlet-red in the arteries to a deep, dark, bluish-red in the veins. Oxygen (and, therefore, the air) makes the blood bright red; Avant of oxygen makes it dark. Blood free from oxygen (and also venous blood) is didirok—i.e., by reflected light it appears dark red, Avhile by transmitted light it is green. [Arterial blood is monochroic.] In thin layers blood is opaque, as is easily sIioaaui by shaking blood so as to form bubbles, or by alloAving blood to fall upon a plate Avith a pattern on it, and pouring it off again. [Printed matter cannot be read through a thm layer of blood spread on a glass slide.] Blood behaves, therefore, like an “ opaque colour,” as its coloining matter is suspended in the form of fine particles—the blood-corpuscles. Hence, it is possible to separate the colouring-matter from the fluid part of the blood by filtration. This is accompli.shed hy mixing the blood with fluids Avhich render the blood- corpuscles sticky or rough. If mammalian blood be treated Avith oue-seventh of its volume of solution of sodie sulphate, or if frog’s blood be mixed with a 2 per cent, solution of sugar {Joh. Muller) and filtered, the shrivelled corpuseles, now robbed of part of their Avater, remain irpon the filter. (2) Reaction.—The reaction is alkaline, OAving to the presence of disodic phosphate, Na.2HP04, and bicarbonate of soda. After blood is shed, its alkalinity rapidly diminishes, and this occurs more rapidly the gi’eater the alkalinity of the blood. This is due to the formation of an acid, in Avhich, perhaps, the coloured corpuscles take part, OAving to the decomposition of their colouring matter. A high
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