CAN THE PRESENCE OF ANTIBODIES TO THE VENOM OF 

 HELODEMA SUSPECTUM BE DEMONSTRATED IN THE 

 BLOOD SERUM OF THIS ANIMAL BY THE METHOD OF 

 COMPLEMENT FIXATION! 



Bt Ellen P. Corson-White. 



An animal secreting a poison deadly to itself would be a rare instance of 

 the preservation of a factor detrimental to the individual and to the race. 

 Many stories of poisonous snakes were found in olden times and out of their 

 mists Francisco Redi (1)* first noted the fact that poisonous snakes were harm- 

 less to themselves. Fontana (2, 3) later gave experimental proof of this immu- 

 nity by forcing vipers to bite themselves or each other. Phisalix and Bertrand 

 (4) confirmed Fontana, and were able to show that harmless reptiles, while less 

 resistant than poisonous snakes, would withstand doses of venom fatal to other 

 animals. Weir Mitchell (5) had previously demonstrated the same fact in 

 cases of the rattlesnake, both when bitten and when the venom was injected 

 subcutaneously or intravenously. Since these observations, auto-immimity 

 has been described in scorpions (6), vipers, black snakes, cobras, and in prac- 

 tically all poisonous snakes. Fayrcr (7), in his study of Indian snakes, says 

 that a serpent not only is not poisoned by its own venom, nor even with that of 

 another individual of its own species, but is only slightly susceptible to the 

 venom of another species. Its venom, however, often kills an innocuous rep- 

 tile; the smaller this serpent and the less poisonous it is, the more readily it 

 succumbs to the poison. Cooke and Loeb (8) have found this same protective 

 power in the Gila monster. Natural immunity, while generally present in 

 snakes, is not absolute (9), and can be overcome by sufficientlj' large doses of 

 venom (10). 



What gives this immunity to snakes? Phisalix and Bertrand (11) thought 

 that the protective power was due to the presence of venom, which entered the 

 blood as an internal secretion from the venom glands of the upper jaw. These 

 glands have been described by many observers — Fontana (2), Leydig (12), 

 Reicht (13), Blanchard (14), Jourdain (15), etc. — in both harmless and poison- 

 ous snakes. 



Phisalix found that the blood of many snakes was distinctly toxic (16) ; if 

 injected subcutaneously or intraperitoneally it produced local and general 

 effects very similar to that produced by venom. These observers removed 

 (17) the poison glands from 46 vipers and 167 days later injected the blood 



*The figures in parentheses refer to the Bibliography on page 198. 



195 



