118 VENOMOUS SNAKES AND THE PHENOMENA OF THEIR VENOMS 



ECHIS. 



As with other genera of Viperince, the poison of Echis much resembles 

 that of Vipera. The venom of Echis carinata acts very much hke that of 

 Dahoia russellii and produces a prompt death in dogs, fowls, pigeons, and 

 other smaller laboratory animals. Local symptoms consist of swelling and 

 discoloration of the bitten part. Faintness, staggering, paresis of the hmbs, 

 and ante-mortem convulsions are the usual symptoms following the bite of 

 this snake or injection of its venom. The coagulability of the blood taken 

 from the bitten animal after its death from toxication is reported by Fayrer 

 as lost. But this observation need not be regarded as evidence against the 

 presence of extensive thromboses in some veins, because, as was pointed out 

 by Lamb, the fluid blood can be collected from such cases. 



THE COLUBRID^, 



The venoms of the snakes belonging to the subfamily Elapinae are remark- 

 able for their powerful neurotoxic and haemotoxic effects with only slight 

 local reactions. Especially is this true with the reptiles inhabiting the Asiatic 

 and African continents. The venoms of certain genera of Elapinse found in 

 Australia also contain considerable of the locally destructive constituents. 

 The symptoms produced by experimental toxications of animals, either 

 through the bite or through injection of the venoms, are described below. 



NAJA. 



The effects produced by the venoms of various species of Naja are essen- 

 tially the same and can be stated in the following sentences. The general 

 symptoms of poisoning by cobra venom are depression, faintness, accelerated 

 respiration and exhaustion, lethargy, unconsciousness, nausea, and vomiting. 

 In dogs, guinea-pigs, and rabbits pecuHar twitching movements occur, which 

 seem to represent vomiting in them, and occasionally dogs and guinea-pigs 

 actually vomit. Profuse salivation is seen in dogs. As the toxication pro- 

 ceeds, paralysis appears, sometimes affecting the hind legs first and seeming 

 to creep up the body, and sometimes affecting the whole animal at once. 

 There is a loss of coordinating power of the muscles of locomotion. Mild 

 haemorrhage, a relaxation of the sphincters, and involuntary evacuations, 

 often of a sanguineous or muco-sanguineous character, may precede death, 

 and are generally accompanied by convulsions. In fowls the appearance is 

 one of extreme drowsiness; the head falls forward, rests on the beak, and 

 gradually the bird, no longer able to support itself, crouches, then rolls over 

 on its side. There are frequent startings, as if of sudden awakening from 

 the lethargic state. 



BUNGARUS. 



The symptoms of toxication by the venom of krait, Bungarus fasciatus, 

 were first accurately observed by Wall, and later confirmed and extended 

 by Lamb. 



