Calcium and Antithrombin in Blood Coagulation. 59 



34 (1098) 



An interrelationship between calcium and antithrombin in blood 



coagulation. 



By Alfred F. Hess, M.D. 



[From the Board of Health Laboratories, New York City.] 



Experiments with dilutions of hirudin show that the stronger 

 the antithrombic solution, the less calcium is needed for optimum 

 coagulation ; in other words that, to a certain extent, they bear an 

 inverse ratio to each other. In the accompanying table we see 

 tests of plasma containing hirudin (1 : 40,000) to which 3, 4, 5 and 

 6 drops of a calcium solution were added. We may note that 

 where only 2 drops of hirudin were added, the clotting-time was 

 in all four instances the same; when three drops were added the 

 time was delayed where 6 drops of calcium were used; and where 

 four drops of hirudin were present, coagulation was markedly 

 delayed in both the tubes containing 5 and 6 drops of the calcium 

 solution. 





Hirudin Solution (Drops). 



Min. 



2 



3 



4 



CaCb 3 drops. 









4 





+ + 



+ 



+ 



8 





+ + + 



+ + + 



+ 



12 









+ 



16 









+ + 



20 









+ + + 



24 



CaCl2 4 drops. 









4 





+ + 



+ 



+ 



8 





+ + + 



+ + + 



+ 



12 









+ + 



20 









+ + + 



24 



CaCh 5 drops. 









4 





+ + 



+ 





8 





+ + + 



+ + + 



+ 



12 









+ + 



28 









+ + + 



44 



CaCh 6 drops. 









4 





+ 



+ 



+ 



8 





+ + 



+ + 



+ 



12 





+ + + 



+ + + 



+ 



20 









+ + 



34 









+ + + 



66 



