126 VENOMOUS SNAKES AND THE PHENOMENA OP THEIR VENOMS 



the size of pulse in uniformity in spite of the reduced blood pressure seems to 

 exclude the possible occurrence of a paretic state in the peripheral vessels. 

 The sinking of blood pressure is better accounted for by the direct weakening 

 of the cardiac activity. The phrenic and sciatic nerves are still excitable to 

 the electric stimulus after death. 



Injection of the venom (o.ooi gm. into the sheath of the sciatic nerve) kills 

 a rabbit with typical symptoms, but haemorrhages spread upwards to the lower 

 third of the medulla along the entire spinal cord, and downwards to the region 

 of the knee. The cord and sciatics are like a dark red string. Small hsemor- 

 rhagic foci occur in the interior of the nervous tissue. 



viperin^;. 



Working with the venoms of European vipers, Vipera berus and Vipera 

 ammodytes?, and of Crotalus, Feoktistow found that, even when a complete 

 paralysis of the extremities had occurred, faradization of the peripheral end 

 of a nerve produced perfectly normal contraction of the muscles. Thus he 

 was unable to find any curare-like effect with these venoms. Paresis and then 

 complete paralysis usually affected the hind legs first, gradually ascending to 

 the front limbs. The reflexes disappeared before or after the onset of paraly- 

 sis. Intravenous injection of strychnine could not reestablish reflex function 

 of the cord, which had lost its reflexes under the effect of the venom. By 

 stimulating the central end of the divided sciatic nerve, even when the hind 

 legs are still in an imperfect paralysis, no movement was obtained in the 

 opposite limb. Dilatation of the pupils is observed in the last stage of venom 

 toxication. 



ELAPINjE. 



Of all venoms of the elapine snakes that of Naja tripudians has been most 

 studied. The literature on this particular venom is very extensive, but I will 

 sum up the results in a compact form. 



In 1874 Brunton and Fayrer 1 contributed many important facts to the 

 nature of the action of Indian snake venoms, dealing especially with the 

 venom of Cobra. As already stated in the description of the symptoms of 

 cobra poisoning, the most prominent symptoms of an affection of the nervous 

 system are depression, faintness, lethargy, and in some cases somnolence. 

 There is loss of coordinating power, with paralysis sometimes affecting 

 the hind legs first and creeping over the body, sometimes affecting the whole 

 body at once. Death occurs by failure of the respiration, and is preceded by 

 convulsions. These symptoms were sought by these authors either in the par- 

 alysis of the nerve centers or of the peripheral nerves. The occurrence of 

 paralysis before the cessation of respiration might have seemed to exclude the 

 possibility of the second alternative, but careful study demonstrated that, 

 although the motor nerves have their function so much impaired that they no 



1 L. Brunton and J. Fayrer. On the nature and physiological action of the poison of Naja tripudians 

 and other Indian venomous snakes. Roy. Soc. Proa, 1874, No. 149, 68. 



