A number of years ago Calmette succeeded in preparing an anticobra venin that has decided protective properties against cobra venom, but it has been shown that this antivenin does not protect against the venom of other snakes, as, for instance, the rattlesnake (Crotalus adamanteus) venom. This is not surprising, however, because we know through the researches of Flexner and Noguchi that the venoms from different species of snakes have a very different constitution. Cobra venom owes its toxicity chiefly to neurotoxin and rattlesnake venom to hemorrhagin which destroys the endothelial cells lining the small blood vessels and causes extravasation of blood into the tissues around the point of inoculation. These venoms contain, however, other toxins beside those mentioned, such as hemolysin, and the rattlesnake venom seems to contain still other substances having a local destructive effect on the tissues.
A number of attempts have been made to prepare an antitoxin