EXPERIMENTAL OBSERVATIONS ON THE COAGULATION OF OXALATED PLASMA, WITH A STUDY OF SOME CASES OF PURPURA

Abstract

Stimulated by Whipple's1 study of the blood-plasma of purpura, and also by the availability of a few patients with purpuric manifestations, we undertook the study, from the point of view of clinical adaptability, of the methods of determining the coagulation properties of the bl ood\x=req-\ plasma of purpura.We found it necessary, however, in connection with this work, to study in detail the general principles of coagulation, and we therefore present our results under the two general heads of (1) "Experimental" and (2) "Clinical Studies." EXPERIMENTAL STUDIESIn the course of our early work we were impressed with the ease of preparing from dog's blood-cells a solution with great thromboplastic activity and comparatively so free from prothrombin or thrombin as to be available as a source of thromboplastin in clinical studies.This solution was prepared as follows: From a normal dog that had fasted twenty-four hours, blood from the jugular vein was allowed to flow into a 1 per cent.sodium oxalate solution in the proportion of nine parts of the former to one of the latter, which was immediately centrifugalized.The clear plasma was drawn off and preserved; the cells were washed three times with 0.85 per cent.sodium chlorid solution and then diluted with three volumes of distilled water.When hemolysis had occurred, 0.85 gram of sodium chlorid was added for each 100 c.c. of distilled water.This is quite similar to the solution of platelets prepared by Bayne-Jones; we have not, however, for our purposes found any advan- tage in isolating the platelets in pure form.To determine whether this solution contained any considerable amount of thrombin or available prothrombin it was mixed with a solu-