6o 



Scientific Proceedings (56). 



36 (853) 



Blood platelets and blood clotting. 



By T. F. Zucker (by invitation). 



[From the H. K. Cushing Laboratory of Experimental Medicine, 

 Western Reserve University, Cleveland, Ohio.} 



That the formed elements of the blood play a part in normal 

 coagulation has long been known. Both leucocytes and platelets 

 have been said to yield substances which contribute to fibrin 

 formation. Leucocytes alone, however, will not coagulate fibrino- 

 gen. Cramer and Pringle 1 have recently shown that oxalate 

 plasma freed from platelets by filtering through clay filters does 

 not clot on adding an amount of CaCl 2 which causes a similar 

 centrifuged but unfiltered plasma to clot in a short time. That 

 platelets disintegrate during coagulation, and that the addition 

 of oxalate preserved them is well known. As early as 1881 Fano 2 

 appreciated the fact that centrifuging was not sufficient to remove 

 all cellular elements, and therefore resorted to filtration through 

 a clay filter. 



Regarding the effect of other anticoagulants, it has been 

 observed by Buerker 3 and by Deetjen 4 that the breaking down of 

 platelets in shed blood as observed under the microscope was 

 inhibited by all those substances which can be used in preventing 

 coagulation. They mention oxalates, citrates, NaPO, Na 2 HPC>43, 

 salts of Mn, Fe and Ni, MgS0 4 , Na 2 C0 3 , peroxides and hirudin. 

 The fact that these substances all have platelet preservative 

 properties, does not necessarily mean that their anticoagulant 

 effect is due solely to the fact that platelets remain intact. 



The experiments of Cramer and Pringle seem to show that 

 oxalate is an anticoagulant because it preserves platelets. That 

 this is more generally the mode of action of anticoagulants is 

 shown by the following data. Citrate plasma gives exactly the 

 same results as oxalate plasma, which has also been verified by 



1 Quart. Journ. Exp. Physiol., 6, I (1913). 



2 Arch. f. Physiol., 1881, p. 277. 



3 Buerker, Pflug. Arch., 102, 36 (1904). 



* Deetjen, Zts. physiol. Chem., 63, 1 (1909). 



