THE COAGULATION OF THE BLOOD 73 
body, but only in certain proportions. Pekelharing considers 
that its action depends upon hindering the formation of pro- 
ferment, ze. kinase, from the corpuscles of blood, but this is 
improbable, since in hirudin-blood all the ccrpuscles are par- 
ticularly well preserved, and on cooling the plasma no 
separation of any granular precipitate can be noticed. The 
differences between hirudin-, peptone-, oxalate-, and fluoride- 
plasma can be seen in the following table, from which it may 
be concluded that in the case of hirudin this substance does 
not remove lime nor neutralise any kinase: 
QO 
° 
or 
otooo+t+o4r+4++ 
Peptone-plasma + Weak acetic 
35 + Water 
Oxalate-plasma + Calcium 
Fluoride-plasma + Calcium 
” + H,O 
Hirudin-plasma + H,O 
+ Calcium 
+ Acetic acid 
eit: Mit tee Mel 
': + Kinase! 
f 
eo 
Hirudin, therefore, exerts its effects by neutralisation of any 
thrombin which may appear. Fuld and Spiro have also shown 
that no neutralisation-ratio exists between thrombo-kinase and 
hirudin. Schittenhelm and Bodong do not hold this view, since 
a solution of fibrinogen containing calcium salts is not prevented 
from clotting by hirudin, and in the case of hirudin-blood the 
action is set aside by a definite amount of thrombo-kinase. These 
authors also draw attention to the fact that a suspension of 
blood-platelets, which after a time spontaneously gelatinises, 
does not pass into this state when hirudin is present. Hirudin- 
blood has also been shown to be markedly resistant to putre- 
factive change, possibly owing to the liberation of alexines from 
the leucocytes. 
Among snake-poisons, the anti-coagulant effect of cobra- 
virus is set aside by the anti-venom prepared by Calmette, 
and Morawitz has shown that the action of the venom is 
dependent on the existence of an anti-kinase. 
1 Depends on the amount of thrombin produced in relation to amount of 
hirudin present. 
