CHAPTER XV. 
HAEMORRHAGINS OF SNAKE VENOM. 
One of the most alarming symptoms of poisoning in the cases of Crotalus 
or viper bites is the enormous swelling and profuse extravasation of blood 
around the wound. Usually these local disturbances set in within 30 minutes 
and increase steadily in intensity and extent up to 24 hours or even a longer 
period, when half of the entire body may be swollen and almost blackish- 
purple in color. The bleeding from the wound often persists a long time. 
In animals, especially in warm-blooded animals, sanguine extravasation and 
swelling are equally grave, and even local sloughing ensues. Cold-blooded 
animals seem to be less susceptible to the hemorrhagic toxin of venom. 
The action of crotalus or water-moccasin venom on the capillary vessels of 
the omentum or mesentery is very rapid and causes an almost immediate 
rupture of the endothelial wall of these capillaries, followed by free escape of 
the blood. This phenomenon can be observed directly under the microscope 
on the mesentery of frog. If we inject a certain amount of crotalus venom 
into the peritoneum of animals, the abdominal tension commences to rise in 
a few minutes and within 30 minutes it is highly distended and becomes 
difficult to compress. In animals killed with rattlesnake venom after intra- 
peritoneal administration a multiplicity of hemorrhages appears almost 
constantly, extending over all the serous membranes, the surface of the visceral 
organs, the diaphragm, the abdominal muscle-layers, the pericardium, the 
pleural surfaces, etc. The peritoneal cavity (and pleural cavity in less degree) 
are filled with bloody exudate. 
In certain marine animals occasionally intracranial hemorrhages and 
haemorrhages from the gills are observed. Certain crotaline venoms, such 
as lachesis venoms, produce severe hemorrhage in the alimentary tract when 
administered through the mouth or rectum. In the pigeon the pectoral 
muscles which receive crotalus venom become thoroughly soaked with the 
blood and are accompanied by a marked softening. 
Now the question arises as to how such extensive and rapid extravasation of 
the blood is produced. Weir Mitchell and Reichert have rightly pointed 
out that the hemorrhages are produced by the venom proteids resembling in 
their physical and chemical reactions the substances classified under the 
general name globulin. Thus these authors prepared at least two varieties 
of globulin, by dialysis precipitation and by copper sulphate precipitation. 
Weir Mitchell demonstrated long ago that the hemorrhagic principles of 
crotalus venom are non-dialyzable, are destroyed at 75° or near 80° C., are 
precipitable but not destroyed by alcoholic treatment, are easily destroyed 
by weak acids but not by weak alkalies, and finally are destroyed in the ali- 
mentary canal by the action of gastric or pancreatic ferments. The dura- 
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