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ON THE COAGULATION OF BLOOD
Author(s) -
Cramer W.,
Pringle Harold
Publication year - 1913
Publication title -
quarterly journal of experimental physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0370-2901
DOI - 10.1113/expphysiol.1913.sp000127
Subject(s) - platelet , calcium , chemistry , coagulation , fibrin , calcium oxalate , oxalate , filtration (mathematics) , thromboplastin , biochemistry , biophysics , inorganic chemistry , immunology , medicine , organic chemistry , statistics , mathematics , biology
Oxalate plasma, when prepared with certain precautions and filtered through a Berkefeld filter, does not clot on the addition of calcium chloride. An investigation of this fact has led to the following conclusions:— Plasma separated from the corpuscular elements in the ordinary way by centrifugalisation at a moderate speed still contains some blood‐platelets. The addition of soluble calcium salts to such plasma brings about in the first instance a breaking down of the platelets. This leads to the liberation of a substance (thrombokinase of Morawitz, thromboplastin of Howell) which is essential for the production of a clot. This substance is not present in freshly prepared oxalate blood in which the platelets have remained intact, and therefore no coagulation takes place on the addition of calcium salts to such plasma, which has been completely freed from platelets by filtration through a Berkefeld filter. Soluble calcium salts, in addition to the primary effect on the platelets, have also a secondary effect in contributing to the formation of fibrin under the influence of the substance liberated by the platelets. Since numerous experiments on blood coagulation have been carried out by previous observers with plasma which was not cell free, but still contained blood‐platelets, it follows that a number of phenomena which have been attributed to the chemical or physical properties of the unorganised constituents of the plasma are in reality due to the behaviour of living cellular elements. The conclusions based on experiments with such plasma require to be revised. In the present paper we have discussed the following phenomena:— The fact that blood remains fluid when caught in paraffined tubes (Freund's method) is explained by the fact that under these conditions the platelets remain intact. The observation of Bordet and Gengou, that plasma obtained from such blood will coagulate when it is transferred to glass vessels, is due to the presence of platelets in such plasma. These platelets disintegrate when brought into contact with glass. The phenomena described by Nolf under the terms “thromboplastic agencies” and “centres of coagulation” are also due to the presence of platelets in the plasma with which he was working. Platelet‐free plasma is not susceptible to the action of “thromboplastic agencies.”