SNAKE VENOMS 1 »•') 



studies of Willsou'"' show about. t(Mi per cent . mortality from all venom- 

 ous snakc-bitcs in this country, the (Uffercnt species giving figures as 

 follows: Coral snakes, twenty to fifty per cent.; water moccasins, 

 seventeen per cent.; large rattlesnakes, eleven to twelve per cent.; 

 copperheads and ground rattlers, no mortality excej)! in children or in 

 cases of complications. The mortality in children is at least double 

 that in adults. Many deaths from snake-bites of all kinds are due 

 to the treatment rather than to the bite. The poisonous snakes of 

 Australia, although numerous, are not very virulent, and the mortality 

 is given as about seven per cent. A full charge of venom from the 

 cobra and many other Indian snakes is inevitably fatal (Fayrer). 

 The crotaline snakes of the tropics are more venomous than those of 

 the north, Lacheris laticeolatus of Central America and Mexico being 

 nearly as dangerous as the cobra. 



When venom is taken into the stomach in the intervals of diges- 

 tion, enough may be absorbed to produce death, especially in the case 

 of those venoms which contain a large proportion of the albumose, 

 which is dialyzable; but during active digestion the venom undergoes 

 alteration and is rendered harmless. It has been found experiment- 

 ally in animals that cobra venom placed in the stomach causes ordi- 

 narily no harm whatever, but if a loop of the intestine is isolated, a 

 fistula established and allowed to heal, venom introduced through 

 this opening always produces death. It is probably not so much 

 the pepsin and hydrochloric acid that destroys the venom, as the 

 trypsin. If the bile-duct is ligated, the venom is destroyed just 

 the same. Much of the venom seems to be eliminated into the stom- 

 ach, no matter how it is introduced into the system, and apparently 

 it is also partly excreted by the kidneys. Rattlesnake venom seems 

 not to be absorbed through mucous membranes. 



Physiological Action. — As indicated in the preceding paragraph, 

 the effects of the bites of different classes of snakes arc quite differ- 

 ent. Langmann describes the symptoms as follows: 



Cobra Poisoning. — "Within an liour, on an average, the first constitutional 

 symptoms ai)pear: a pronounced vertigo, quickly followed by weakness of the 

 legs, which is increased to paraplegia, ptosis, falling of the jaw with paralysis 

 of the tongue and epiglottis; at the same time there exists an inability to speak 

 and swallow, with fully preserved sensorium. The symptoms thus resemble those 

 of an acute bulbar paralysis. The pulse is of moderate strength until a few 

 minutes after the cessation of respiration; the latter becomes slower, labored, 

 and more and more superficial until it dies out almost impe.ceptibly. Death 

 occurs at the latest within fifteen hours; in 32 per cent, of all cases in three hours. 

 There are very few local changes." Cushny" finds that cobra venom produces 

 paralysis of the motor nerve terminations of .muscle, resembling the action of 

 curare; the central nervous system is not directlj^ involved. Death recults from 

 failure of the moto ■ nerve ends in the respiratory muscles to transmit impulses 

 to the muscles. Alkaloids that are antagonistic to curare (physostigmine, guani- 

 dine) are not effective in cobra poisoning, but are them,selves rendered inactive. 



"« Arch. Int. Med., 1908 (1), 516. 



" Trans. Roy. Soc, London (B), 191(5 (208), 1. 



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