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?]
Catalogue details

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.

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    under cool running water. Under the running water, also, a trimmed feather was introduced into the cannula and the tube to push out the plasticine and to wash out the blood. Wire, cannula and tube were then dropped into a beaker receiving running hot water (about 80° C) and there allowed to remain for about five minutes. On removal from this the parts were shaken free from water, passed through 95 per cent alcohol and again shaken free, passed through ether and let dry. By having a half-dozen cannulas and wires of standard size, it was possible to save trouble by cleaning a number at one time. Not infrequently the first few samples of blood taken from an animal showed rapid or somewhat irregular rates of clotting. Some causes for these initial variations will be presented in follow- ing papers. The fairly uniform rate of clotting in any individual after the initial stage, varied in 21 different animals from an aver- age of 3 to an average of 10.6 minutes, with a combined average of 5.9 minutes. The conditions for these variations among indi- viduals have not been wholly determined. The method here described has been employed not only to determine the coagulation time of cat’s blood, but also that of human blood taken repeatedly through the skin at the base of the thumb nail. The skin was washed in soap and water, and rinsed in alcohol and ether before each test and then punctured with a sharp, well-pointed, three-cornered needle. The drop of blood that appeared on the skin was drawn into the cannula, and then the procedure was that above described. Following are figures ob- tained on one occasion: Coagulation time Variations from the average 5.5 minutes + 0.6 minutes 5 ie -Ot- “ AS. —-04 * iia —-04 * ie ee Average 4.9 minutes Average error + 0.3 minutes Per cent average error = 6. Doubtless if the lever were moved more frequently than every half-minute the average error would be reduced.
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