ORDER OPHIDIA. 319 



manifest themselves in the following manner, particularly 

 after the bite of the viper. 



An intense and stinging pain is felt in the place where the 

 wound has been made, which soon becomes the seat of an 

 inflammatory swelling, with a tendency to gangrene, which 

 is indicated by livid spots. At the same time the wounded 

 person experiences nausea, weakness, vertigo, syncopes, diffi- 

 culty of breathing, confusion in the intellectual faculties, 

 vomitings of bilious and yellowish matter, convulsive move- 

 ments, and pains in the umbilical region. All these are 

 signs of the general impression produced by the virus on the 

 entire system ; not that it coagulates the blood on the vessels, 

 as Fontana concluded from illusory experiments, but because 

 it exercises a special action on the principle of sensibility. 



The blood which flows at first from the wound is often black- 

 ish. Soon after it is replaced by sanies, and the gangrene 

 declares itself when the malady is about to terminate by death. 

 This termination is happily not the most usual, at least 

 in the case of the bite of vipers. It is not even so common 

 as it is universally supposed to be in the case of other species 

 of venomous reptiles. In the sitting of the Royal Aca- 

 demy of Sciences, in Paris, in April 1827, Professor Bosc 

 declared that he had seen more than thirty persons who had 

 been bitten by rattle- snakes, not a single one of whom had 

 died in consequence. 



Fontana having ascertained that a hundreth part of a 

 grain of the poison of a viper, introduced into a muscle. 

 Was sufficient to kill a sparrow, and that six times as much 

 was necessary to destroy a pigeon, has calculated that it 

 will take pretty nearly three grains to kill a man. Now 

 as a viper has but about two grains of poison in its vesicles, 

 which it does not exhaust even after many bites, it would 

 seem evident that a man might receive, without dying in conse- 

 quence, the bite of five or six vipers. Such, however, is not 



