EFFECTS OF SNAKE VENOM ON COAGULABILITY OF THE BLOOD 137 
the quickest and firmest coagulation, while the doses above these quantities 
reduced or annihilated the coagulability. Thus 0.003 gm. still produced 
a loose coagulation, while 0.004 gm. doses and upwards (tried up to o.o1 
gm.) did not produce further coagulation. 
The venoms of the following snakes possess coagulating power in the 
order given: 
CroraLina@: Lachesis lanceolatus (Bothrops), Martinique; L. urutsu (neu- 
wiedii), Brazil; L. jararaca, Brazil; L. jararacussu, Brazil; 
L. flavoviridis s. Trimeresurus riukiuanus, Japan. 
VIPERIN#: Vipera russellii (daboia), Burma. 
As to the mechanism of the coagulating action of the venom, Noc is inclined 
to consider it to be a part of activation of the plasmase (or fibrin ferment) by 
venom. Thus, venom may act something like some organ extracts in bring- 
ing the zymogenic form of fibrin ferment (protothrombin or thrombogen) 
into an active state, although no definite processes are yet known. He does 
not, however, exclude the possibility that venom contains a veritable fibrin 
ferment. 
The rapidity with which coagulation of the citrate or oxalate blood takes 
place under the influence of these venoms renders it improbable that the 
destruction of the red corpuscles has any relation to this phenomenon. At 
any rate, the venoms of Lachesis do not alter the corpuscles for some time 
after they are mixed. 
Noc also found that the venoms of Naja tripudians, Naja nigricollis, and 
Bungarus ceruleus were devoid of coagulating property on the whole blood 
or the plasmas which were rendered incoagulable by these anti-clotting salts 
or leech extract. This agrees with the negative observations of Lamb with 
the venoms of Cobra and kraits. 
The peculiar phenomenon that a too large amount of lachesis venom, 
when mixed in vitro, produces incoagulability of the blood is attributed by 
Noc to the fibrin-dissolving property of the venom. ‘That crotalus venom 
in a strong concentration in vitro results in the same fluidity of the blood 
has been shown by S. Weir Mitchell and Reichert. 
Martin found that the coagulating property of the Australian snake venoms 
disappeared after heating to 80° C.' for half an hour, and Lamb found the 
same result for daboia venom after heating to 75° C. during half an hour; 
finally, Noc, for the lachesis venom, found that there was much weakening 
at s8° C., and complete destruction at 80° C. maintained for the same period 
in a sealed tube. Noc further found that alcohol precipitates, but does not 
destroy, the coagulating principle of the lachesis venom. 
In rg05 Martin? made further contributions to our knowledge of the 
coagulating constituents of the venoms of Pseudechis porphyriacus, Notechis 
scutatus, Echis carinata, and Daboia russellii. Of these four venoms that of 

1A weaker solution, viz, 0.1 per cent, is completely destroyed at 75° C. for ro to 15 minutes. _ 
2C. J. Martin. Observations upon fibrin ferments in the venoms of snakes and the time-relation of 
their action. Jour. of Physiol., 1905, XXXII, 207. 
