CHAPTER XV. 

 H/EMORRHAGINS 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 haemorrhagic 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 haemorrhages 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 haemorrhages and 

 haemorrhages from the gills are observed. Certain crotaline venoms, such 

 as lachesis venoms, produce severe haemorrhage 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 haemorrhages 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 haemorrhagic principles of 

 crotalus venom are non-dialyzable, are destroyed at 75 or near 8o° 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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