Factors affecting the coagulation time of blood. I, The graphic method of recording coagulation used in these experiments / by W.B. Cannon and W.L. Mendenhall.
- Walter Bradford Cannon
- Date:
- [1914?]
Licence: Public Domain Mark
Credit: Factors affecting the coagulation time of blood. I, The graphic method of recording coagulation used in these experiments / by W.B. Cannon and W.L. Mendenhall. Source: Wellcome Collection.
3/12
![Reprinted from the American Journal of Physiology Vol. XXXIV — May 1, 1914 — No. II FACTORS AFFECTING THE COAGULATION TIME OF BLOOD ! I. THe Grapuic METHOD OF RECORDING COAGULATION USED IN THESE EXPERIMENTS By W. B. CANNON anp W. L. MENDENHALL [From the Laboratory of Physiology in the Harvard Medical School] Received for publication March 30, t9r4 ANY methods have been devised for determining coagulation time. The description of these methods is unnecessary in this paper, for they have been considered critically in two com- paratively recent reviews, one by Addis,? the other by Morawitz.® With different methods the coagulation time of blood (at 20°) has been set down as ranging from approximately 5 minutes (Addis) to 20 minutes (Morawitz and Bierich). This great discrepancy shows that there is no definite “coagulation time”’ quite independ- ent of the method used, i.e., the conditions peculiar to.any coagu- lometer are likely to affect the time of clotting. Since to drawn blood any instrument is a foreign body, all that is required of an instrument is that the conditions of its use shall be constant. The conditions defined by Addis as being essential for accurate estimation of coagulation time are as follows: t. The blood must always be obtained under the same condi- tions. 2. Estimates must all be made at the same temperature. 3. The blood must always come in contact with the same amount and kind of foreign material. 1 A preliminary report of these experiments was presented at the meeting of the American Physiological Society, Dec. 29, 1913. See Proceedings, This journal, 1914, xxxiii, p. xxxviii; also p. 372. 2 ADDIS: Quarterly journal of experimental physiology, 1908, i, p. 305. 3 Morawitz: Abderhalden’s Handbuch der biochemischen Arbeits- methoden, 19011, v, pp. 235-252.](https://iiif.wellcomecollection.org/image/b33443725_0003.jp2/full/800%2C/0/default.jpg)
