226 VENOMS 
A number of experiments have been made by Lewin,’ and by 
Phisalix and Bertrand,? upon the immunity of the hedgehog to the 
venom of Vipera berus. 
It had long been known that hedgehogs are inveterate hunters 
of vipers, which they devour with avidity. Thanks to the long and 
sharp spines by which their bodies are protected, they avoid being 
bitten and contrive to catch the reptiles very cleverly, but it 
occasionally happens that they do not escape being struck. How- 
ever, even in these cases they rarely succumb. 
Inoculation with fairly large quantities of venom does not make 
them ill: the dose of viper-venom lethal for these small animals 
is about forty times greater than that which kills the guinea-pig. 
Their power of resistance is therefore beyond doubt. 
It may be asked whether this is due to their blood normally 
containing antitoxic substances. In order to elucidate this question, 
Phisalix and Bertrand first proved that the blood of normal 
hedgehogs is toxic to laboratory animals, especially to the guinea- 
pig. A mixture of this blood with viper-venom cannot therefore 
be harmless. But it sufficed to heat hedgehog blood to 58° C. to 
cause it to lose its toxicity, and it was found that it then became 
antitoxic. Guinea-pigs inoculated in the peritoneum with 8 c.c. 
of heated hedgehog-serum were able to withstand, immediately 
afterwards, twice the lethal dose of viper-venom. 
It really seems, therefore, that the resistance of the hedgehog 
to venom is due to the presence of antitoxic substances in its 
blood. But, as in the case of the mongoose, there is no question 
here of genuine immunity. 
The same is probavly true with respect to the herons of 
Colombia, the Culebrero and Guacabo, which eagerly search after 
' Deutsche medicinische Wochenschrift, 1898. 
? Comptes rendus de la Société de Biologie, 1895, p. 639, and 1899, p. 77; 
Bulletin du Muséum d'Histoire naturelle, 1895, t. i., p. 294, t. ii., p. 100. 
