172 C. J. MARTIN. 
negative phase, for blood drawn three minutes after the injection, 
either fails to clot at all, or does so only after the lapse of several 
hours. The negative phase continues for one or two days aitet : 
the introduction of the poison in dogs which have received a neatly : 
fatal dose of the venom subcutaneously. . 
It is interesting to note that the duration of the phase d 
diminished coagulability corresponds under such cireumstant 4 
with the period of blood cell destruction. When this cell destrue ‘ 
tion ceases, the coagulability of the plasma rapidly returns to the 
normal. The blood in all parts of the vascular ‘system does not 3 
exhibit the same tendency to clot in the vessels, When dogs . 
are the subjects of experiment, coagulation, when present, always 
occurs in the portal venous system, and the thrombosis 8 
frequently confined to this area. It also occurs more readily : 
with venous than with arterial blood. 
Dogs evince varying degrees of susceptibility in this respech 
the same dose per kilo. producing in one animal intravasculat 
clotting, in another inhibition of the coagulation of the shed blood. . 
Results with animals other than dogs. . 
T have examined the condition of the blood after the intravenoe 
injection of snake poison in rabbits and cats. In these 
both positive and negative phases occur as with dogs. Cats apP 
more resistant to the action of the venom than dogs and rahi ; 
Conditions modifying the effect upon the blood plasma of the 
injection of venom. : 
(1) Influence of Respiration. 
T have previously mentioned that I have on no occasion 05 : 
the blood, which has just traversed the capillaries of the lungs 
participate in an otherwise general thrombosis. Whatevt "= 
may be effected in the plasma during its passage through : 
pulmonary veins and left auricle, where it remains fluid, e oo 
transient for the blood in the left ventricle and aorta is often ae 
When complete clotting of the blood in both systemic om 
and veins follows injection of the poison, respiration cont" a 
