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.

Landois, L. (Leonard), 1837-1902. Lehrbuch der Physiologie des Menschen. English

Date:: 1891

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.

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$nature of a ferment, although they use the term for convenience. It is quite certain that fibrin may be formed when no fibrino-plastm is present, coagulation beino- caused by the addition of calcic chloride or casein prepared in a special way. One*^of the conditions necessary for the action of fibrin-ferment on fibrinogen seems to be the presence of neutral salts. If the latter be completely removed the formation of fibrin does not take place. Lime salts seem to be m some way essential to the process, e.g., calcic sulphate, while others attach importance to the presence of I^aCl.] ., [The main drift of the foregoing evidence points to the presence of one proteid —fibrinogen—which exists dissolved in the blood-plasma, and which under certain circumstances yields fibrin. In shed blood this act seems to be determined by a ferment, perhaps derived from the disintegration of colourless corpuscles (and blood-platelets 1), which occurs when blood is shed.] [It must not be forgotten that the presence of certain salts seems necessary to the act of coagulation. As the question at present stands, three factors are recog- nised in the equation :— (1) A coagulable proteid (fibrinogen). (2) A ferment. (3) Certain salts. Up till recently the first two have attracted the greatest amount of attention, but that the third factor is also an important one is shown by the above-mentioned researches.] 30 SOURCE OF THE FIBRIN-FACTORS—Al. Schmidt maintains that all the three substances out of which fibrin, according to him, is formed arise from the breaking up of colour- less blood-corpuscles. In the blood of man and mammals fibrinogen exists dissolved m the circulating blood as a dissolution-product of the retrogressive changes of the white corpuscles. Plasma contains dissolved fibrinogen and serum-albumin. The circulating blood is very rich m colourless blood-corpuscles-much richer, indeed, than was formerly supposed. As soon as blood is shed from an artery, enormous numbers of the colourless corpuscles are dissolved- according to Al. Schmidt, 71-7 per cent, (horse). First the body of the cell disappears, and then the nucleus. The products of their dissolution are dissolved m_ the plasnaa, and one ot these products is fihrino-plastin. At the same time the fibrin-ferment is also produced, so that it would seem not to exist in the intact blood-corpuscles. Fibrino-plastm and fibrin-ferment are also produced by the transition forms'' of blood-corpuscles, 1.. those lorms which are intermediate between the red and the white corpuscles. They seem to bi;eak up immediately after blood is shed. The hlood-plates (p. 19) are also, probably, sources of these substances. The leucocytes have difterent degrees of resistance ; those of the lymph and chyle are more resistant than those of the blood, and amongst the latter themselves there are various degrees ^^Iif amphibians and birds the 7-^^^ nucleated corpuscles rapidly break up after blood is shed and yield the substance or substances which form fibiin. Al Schmidt convmced himself that in these animals fibrinogen is originally a constituent of the blood-corpuscles. It is clear, therefore, according to Schmidt's view, that as soon as the blood-corpuscles white or red, are dissolved, the fibrin-factors pass into solution, and the formation of fibim by the interaction of the three substances will ensue. . , ^. , . wu„ If a large number of leucocytes be introduced into the circulation of an animal, the leucocytes are dissolved in great numbers in the blood, so that death takes place by diff-use coagulation Should the animal survive the immediate danger of death, the blood, owing to the want ot leucocytes, is completely incapable of coagulating {Groth). . j ^^ a ^ ..^.;AaA in [And. Buchanan thoiight that the potential element of his ' washed blood-clot les^ded in the colourless corpuscles, primary cells or vesicles. He hke Schmidt, f«^^ ^^j^*Jc^^^ buffy coat of horses' blood, which is very rich in white corpuscles, produced coagulation rapidly. Buchanan compared the action of his washed clot to that of rennet ii^C'-^^g^^f ^mg milk. J Pathological.—Al. Schmidt and his pupils have shown that some ferment, probably derived from the dissolution of colourless corpuscles, is found in circulating blood, and that it is more abundant in venous than in arterial blood, while it is most abundant m shed blood It is specially remarkable that in septic fever the amount of ferment in blood may increase o such an extent as to permit the occurrence of spontaneous coagulation (thrombosis), which may even produce death {Arn. Köhler). In febrile cases generally, the amount of ferment is soinewhat more abundant {Melberg and Birk). After the injection of ichor into the blood an enoimous$