120 VENOMOUS SNAKES AND THE PHENOMENA OF THEIR VENOMS 
the circulation. In dogs doses over 0.0001 gm. per kilo body-weight produce 
extensive intravascular (arterial and venous) thrombosis and death may 
occur within several minutes. The respiration is seen to continue I or 2 
minutes after the heart ceases to beat. When the concentration falls short 
of that necessary to raise the coagulability of the blood sufficiently to cause 
thrombosis, the blood shortly afterwards loses its capacity to clot when with- 
drawn. In this condition any further injection of venom fails to produce 
thrombosis. 
The action of the poison upon the heart and respiratory center is usually 
simultaneous. But with higher concentration of the venom the heart is more 
rapidly affected than the respiration, so that by varying the rapidity with 
which the venom reaches the circulation, the death of an animal may be com- 
passed in any one of three ways: either by clotting the blood in the vessels, 
cardiac failure, or respiratory paralysis. If animals escape the three possi- 
bilities of fatal issue above mentioned, they may succumb to the effects of the 
pathological changes in the lungs and kidneys. This last danger is, however, 
not a large one, except with dogs, and the animals usually recover with wonder- 
ful rapidity. 
Violent convulsions are always observed in cases in which death results 
from the intravascular thrombosis, and is due to the effect of asphyxia. In 
cases where death is due to the paralytic action of the venom upon the nervous 
system, there is first uneasiness, then lethargy, and often vomiting. The 
lethargy increases and is succeeded by weakness, which first affects the hind 
quarters. The animal remains quiet, and is disinclined to move. If forced 
to walk its gait is unsteady and lacks coordination. Later it is quite unable 
to stand, the pupil becomes dilated and insensitive to light, and breathing is 
shallow and slower. Reflex action gradually disappears, and the respiration 
becomes very sluggish and gasping, and ultimately ceases. Death is followed 
usually, but not always, by a few feeble, convulsive movements. 
DISTIRA. 
The symptoms observed in animals after the bite or injections of the venom 
of the Hydrophiine are similar to those of cobra-venom toxication. The local 
symptom is, however, very slight; and there are no symptoms pointing to any 
action of the venom upon the coagulability of the plasma or on red corpuscles. 
Progressive paralysis is accompanied by dyspneea. 
The symptoms produced by the bite of Distira cyanocincta on fowls depend 
upon the amount of the poison introduced into the system. The bite may 
kill a fowl within a minute or death may occur after 10 to 20 minutes, accom- 
panied by paralytic symptoms. The fangs are very minute and often fail to 
make distinct marks at the spot of the bite, although slight bleeding may 
sometimes result. Local reaction is entirely negligible. This snake is rather 
active and may voluntarily bite the animal brought before it. Coagulability 
of the blood usually remains unaltered from the effect of its bite. The symp- 
