THE COAGULATION. OF “THE BLOOD 67 
vascular clotting. Outside the body the morphological con- 
stituents of the blood, and in particular the blood-platelets, yield 
kinase when these are brought in contact with non-living matter. 
The first phase of the coagulation process is thus initiated by 
the co-operation of thrombogen, calcium ions, and kinase. 
BLOOD 
Plasma Cells 
Thrombogen Thrombo-kinase 
catia 
| converts fibrinogen 
a-Thrombin” ~7 into fibrin. 
SERUM 
Thrombin Metathrombin 
by alkali 
Thrombogen 8-Thrombin 
The following table shows the accepted constituents of 
various plasmata on the suggested hypotheses of Morawitz, 
Fuld, and Spiro: 
‘Ser Gee Bed | Seri bas | Sees} nei feat 
Pe se Ehrombogen. +? + | + + a + 
Kinase . fo) +? fo) + +? + 
Thrombin | fo) + fe) fe) fe) fe) 
Metathrombin | fe) + fe) fe) fe) oO 
Calcium “| a5 a5 + fe) fe) a= 
Of the substances concerned in the production of thrombin, 
as described in the account just given, it would appear that very 
definite knowledge as to the sources or nature of thrombo- 
kinase and thrombogen in coagulable liquid does not exist. It 
is possible that kinase corresponds entirely or in part to the 
nucleo-proteid which apparently enters into the composition of 
the blood-platelets. | Fluids such as goose-plasma, fluoride- 
plasma, or hirudin-plasma are devoid of kinase, while in oxalate 
or peptone-plasma this is present. On cooling these plasmata 
a granular precipitate occurs only in those which possess kinase, 
and this deposit is recognised in part to be nucleo-protein. 
As to the source or sources of thrombogen in blood there is 
