6 



Scientific Proceedings (55). 



3 (820) 



On the role played by antagonistic ions in the process of blood 



coagulation. 



By G. H. A. Clowes and F. West. 



[From the Biological Chemical Department of the State Institute for 

 the Study of Malignant Diseases, Buffalo, N. Y.] 



Citrated plasma prepared by admixing three parts of blood 

 with one of 2.38 per cent, sodium citrate and centrifuging, coagu- 

 lates almost immediately when admixed with an amount of CaCl 2 

 chemically equivalent to 4/10 to 3^ of the citrate present. If 

 additional citrate is added to the plasma, it is necessary to pro- 

 portionately increase the amount of calcium added to induce 

 coagulation. With thrombin, however, coagulation of plasma 

 takes an entirely different course, the velocity of coagulation is 

 considerably slower, but is apparently entirely uninfluenced by 

 an excess of citrate. It may be concluded, therefore, that calcium 

 induces coagulation by liberating thrombin from the blood plate- 

 lets or other cells present in suspension in the plasma. To throw 

 further light on this point, equal volumes of the same citrated 

 plasma were precipitated by means of a considerable excess of a 

 mixture of acetone and ether (an agent which has proved of con- 

 siderable value in the preparation of thrombin) an excess of calcium 

 chloride being added in one case immediately before and in the 

 second case immediately after precipitation. The mixtures con- 

 taining acetone ether were evaporated in vacuo at room tempera- 

 ture, the residues taken up with water and added to further 

 amounts of citrated plasma to which an excess of citrate had 

 previously been added. In the first case in which the calcium 

 chloride was added before precipitation, coagulation took place 

 rapidly, indicating the presence of free thrombin. In the second 

 case in which the calcium was added after precipitation, no co- 

 agulation took place on addition of plasma, from which it must 

 be concluded that by the process of precipitation the cells contain- 

 ing the thrombin have been rendered resistant to the action of 

 calcium. Since the acetone-ether mixture removes not only water 

 but fats, and since the precipitated material re-suspended in 



