CHAPTER XX. 



ANTIBACTERICIDAL PROPERTIES OF SNAKE VENOM. 



S. Weir Mitchell has repeatedly pointed out the danger of a secondary 

 bacterial infection in the subject which survives the primary fatal effects of 

 snake venom, and also of the rapid decomposition of cadavers dead of venom 

 toxication. He perceived that there must be a definite alteration produced 

 by venom in the preservative properties of the tissues, but did not establish 

 this point on an experimental basis. 



In 1893 William H. Welch, together with C. B. Ewing, 1 finally discovered 

 that rattlesnake venom has the property of annihilating the bactericidal 

 power of the blood. A rabbit was fatally poisoned with venom and just 

 after its death the blood was collected from the large veins. Control blood 

 was obtained from a healthy rabbit. The bactericidal power was tested by 

 introducing into the serums obtained from those bloods, cultures of the 

 anthrax bacillus and of cholera bacillus. It was found that while normal 

 serum destroyed thousands of the respective bacilli, the venomized serum 

 had lost this power. It is supposed that the rapid decomposition of the bodies 

 of those who die of snake poisoning, as well as the extensive suppuration 

 from which they suffer, may depend upon this cause. 



An exhaustive study of the same phenomena was next made by Flexner 

 and Noguchi, 2 and the results are briefly mentioned below. The animals 

 employed were the dog, rabbit, and Necturus; the venoms belonged to the 

 cobra, moccasin, copperhead, and rattlesnake, and the bacteria were B. lyphi, 

 B. coli, and B. anthracis. The method consisted in - 



(1) Introducing venom into the animal and drawing the blood from the 

 femoral artery into sterile Nuttall bulbs. 



(2) Permitting the blood from the normal animal to enter Nuttall bulbs in 

 which the venom solution was contained. 



(3) Admixture of the venom in sterile solution (heated for 4 days to 56 

 to 60 C., 30 minutes each time) with separated serum. 



The bactericidal effects of the normal serums were first established. Rabbit 

 serum is highly destructive for B. typhi and B. anthracis and least for B. coli. 

 Dog serum is highly destructive for B. typhi. Necturus serum is also very 

 destructive for B. typhi and B. coli, but without marked effects on B. anthracis. 



(i) Serum venomized in vivo: Cobra venom was most active. Blood 

 from rabbits which had received o.oi gm., taken 57 minutes after injection - 



1 Welch and Ewing. The action of rattlesnake venom upon the bactericidal properties of the blood. 



Trans, of the First Pan-American Medical Congress, Washington, 1893, I, 354-. 



2 Flexner and Noguchi. Snake venom in relation to haemolysis, bacteriolysis, and toxicity. Jour, of 



Exper. Medicine, 1902, VI, 277. 



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