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THE COAGULATION TIME OF THE BLOOD IN MAN
Author(s) -
Addis T.
Publication year - 1908
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.1908.sp000023
Subject(s) - coagulation , citric acid , degree (music) , constant (computer programming) , yield (engineering) , mathematics , chemistry , surgery , medicine , thermodynamics , computer science , physics , biochemistry , acoustics , programming language
1. There are four conditions which must be fulfilled by any method which is to yield results which can be relied upon. (a) There must be a uniform method of obtaining the blood. (b) The temperature must be the same during each experiment. (c) The amount of contact with foreign bodies must be always the same. (d) The end‐point must be clear and definite and such as always to indicate the same degree of coagulation. 2. A method is described which conforms to these conditions. 3. Other methods which have been employed are reviewed, and, where necessary, the result of work undertaken to test their accuracy is given. 4. The general conclusion of this testing is that no one of these methods fulfils all the conditions mentioned above, and that in particular all fail to comply with the essential condition that in comparative observations exactly the same temperature must be maintained throughout. 5. The effect of variations of temperature is described, and it is shown that at about the normal temperature of the body the coagulation time is shortest, becoming gradually longer at temperatures above 40° C. and below 36° C. 6. The coagulation time is constant for the same individual at different times of the day, and even on different days. The daily variations which have been described do not exist, but are due to fallacies in connection with the methods which have been employed. 7. The conclusion that calcium and citric acid, when administered by the mouth, have no effect on the coagulation time, is referred to. I wish to express my thanks to Professor Schäfer and to Dr Cramer for advice and criticism during the progress of these investigations. The expenses entailed have been defrayed by a grant from the Moray Fund of the University of Edinburgh.