116 VENOMOUS SNAKES AND THE PHENOMENA OF THEIR VENOMS 
The inflammatory hemorrhagic focus becomes necrotic and may form a 
crust and be cast off or may be absorbed. 
The intravenous administration of the habu venom into rabbit and dog 
brings about rapid reduction of blood pressure with the frequence and size of 
pulse almost unaltered. Ishizaka believes that the vasomotor nerve is not 
paralyzed, as the blood pressure can increase in a later stage of toxication 
when the artificial respiration is suspended. The irritability of the splanchnic 
nerve is greatly diminished, but never abolished completely. He also points 
out that the peripheric vessels are not markedly relaxed. Respiratory fre- 
quency is not affected at the beginning, but it lessens gradually and finally 
disappears. Judging from the presence of the irritability of the phrenic and 
sciatic nerves after death, the failure of respiration is ascribed to the central 
paralysis. 
By intravenous injection in rabbits and dogs hemorrhages are produced 
in internal organs, especially in the pericardium, endocardium, and gastric 
mucous membrane. In dogs the internal hemorrhages appear to be more 
frequent and also present in the lungs, mesenterial membrane, and intestinal 
tract. On the other hand, administration of the venom per anum did not 
kill the rabbit when 3.25 gm. were given in divided doses, but killed it when 
a single dose of 0.34 gm. was given. In this case there was no hemorrhage 
in the mucous membrane, but the histological examination of the kidney 
showed parenchymatous nephritis. 
Under no conditions was Ishizaka able to produce bloody urine or hemor- 
rhages in the brain, spinal cord, and their membranes, or in the bone marrow. 
VIPERA. 
Vipera russellii or Daboia is one of the most dreaded snakes in India and 
its venom is known to cause death with a lightning rapidity when sufficiently 
injected into the victim. The cause of this quick death has since been dis- 
covered to be due to its large content of fibrin ferment capable of producing 
instantaneous intravascular thrombosis. As to this property of daboia venom 
and venom in general I will give fuller details in a later chapter. Fayrer and 
Brunton studied the action of this venom very carefully and the former gives 
many interesting experiments of the effects of the daboia bite on various 
kinds of animals. Dogs, cats, and fowls succumbed to a single bite, with the 
symptoms of pain, swelling, and paralysis of respiratory center. Convulsions 
were almost constant before death. The blood was found to have lost its 
coagulability. Horses were allowed to be bitten by Daboia, and these were 
always killed. Respiration was affected most and seemed to be the cause 
of death, although always accompanied by general weakness. The blood 
remained fluid. One experiment with an ox showed that the bite of Daboia 
fails to kill even if its fangs take effect. There was, however, great swelling 
and general weakness lasting for a few days. 
A more accurate study of this venom has been made by Lamb, who mostly 
employed monkeys, rabbits, rats, and pigeons. 
