Kirkes' handbook of physiology. / By W. Morrant Baker and Vincent Dormer Harris.

  • William Senhouse Kirkes
Date:
1888
Catalogue details

Licence: Public Domain Mark

Credit: Kirkes' handbook of physiology. / By W. Morrant Baker and Vincent Dormer Harris. Source: Wellcome Collection.

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

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    the microscope, the fibrin fibrils are seen to start from the colonr- less corpuscles. Although the intimate connection of the coloiirless corpuscles with the process of coagulation seems indubitable, for the reasons just given, tlie exact share which they have in contributing the various fibrin factors still remains uncertain. It is generally believed that the fibrin-ferment at any rate is contributed by them, inasmuch as the quantity of this substance obtainable from plasma bears a direct relation to the numbers of colourless corpuscles which the plasma contains. Many believe that the fibrinogen too is wholly or in part derived from them, and also that they are the usual source of the paraglobulin present in plasma. According to this view all the fibrin factors are derived from the disintegration of the colourless corpuscles. We have seen that the coloured corpuscles may also under certain circum- stances take a share in producing the fibrin generators. Conditions affecting Coagulation.^—The coagulation of the blood is hastened by the following means :— 1. Moderate warmth,—from about ioo° to 120° F. (378— 49° C.). 2. Best is favourable to the coagulation of blood. Blood, of which the whole mass is kept in uniform motion, as when a closed vessel completely filled with it is constantly moved, coagulates very slowly and imperfectly. 3. Contact with foreign matter, and especially multiplication of the points of contact. Thus, as before mentioned, fibrin may be quickly obtained from liquid blood by stirring it with a bundle of small twigs; and even in the living body the blood will coagulate upon rough bodies projecting into the vessels. 4. The free access of air.—Coagulation is quicker in shallow than in tall and naiTOw vessels. 5. The addition of less than twice the bulk of tvater. The blood last drawn is said, from being more waterj^, to coagu- late more quickly than the first. The coagulation of the blood is retarded, suspended, or prevented by the following means :— I. Cold retards coagulation; and so long as blood is ke]it at a temperature, 32° F. (0° C), it will not coagulate at all. Freezing the blood, of course, prevents its coagulation; yet it will coagulate, though not firmly, if thawed after being frozen ; and it will do so,
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