264 



VENOMOUS ANIMALS 



Tables are given by Calmette, and Martin and Lamb, showing 

 the amount for different snakes and animals. Thus, the quantity 

 of cobra -venom required to kill a kilogramme of a dog is o-ooo8 

 gramme, and of a rabbit 0-0005; and that of Bungarus candidus 

 for a rabbit is o-ooo8 gramme, and that of Enhydrina valakadien 

 for a rabbit is 0 -00006 gramme, while the same for a cat is 0-0002. 

 Putting it in another way, i gramme of cobra-venom will kill 

 1,250 kilogrammes in weight of a dog, 2,000 of rabbit, 2,500 of 

 guinea-pig, 1,500 of rat, and 8,333 of mouse, and 20,000 grammes 

 of horse. 



Calmette calculates that, taking a man of average size, the 

 minimum lethal dose might be halfway between the dog and the 

 horse — i.e., would be 0-015 gramme of cobra-venom — and i gramme 

 will kill 10,000 kilogrammes of man, or 165 persons of the weight 

 of 60 kilogrammes; but, of course, this is only a very approximate 

 guess. Lamb calculates the M.L.D. for man to be 0-015 gramme 

 of cobra-venom, and Fraser puts the same at 0-031 gramme, while 

 other authors give cobra M.L.D. for man 0-010 gramme and echis 

 M.L.D. the same figure. 



Lamb gives a number of minimum lethal doses for snakes cal- 

 culated per kilogramme of rabbit and injected intravenously, which 

 are : — 



Bungarus candidus . . . . . . 0-00004 gramme. 



Enhydrina valakadien . . . . 0'00005 



Vipera russellii . . . . . . O'oooi 



Naja tripudians and N. bungarus . . 0'00035 

 Bungarus fascia tus . . . . . . 0-0007 



Effects of the Venom. 



The effects of the venom have been carefully studied on warm 

 and cold blooded animals by many observers for a long series of 

 years, but there is a distinct difference in the action of different 

 kinds of venom, and therefore it is as well to discuss the effect of 

 each separately. 



In doing this it will be noted that it is difficult to obtain un- 

 doubted cases of bites by definitely known snakes in man, and 

 even when these are obtained the urgent necessity for treatment 

 causes the symptoms to be little noted. Therefore it is necessary 

 to detail first the experiments on animals, and then the symptoms 

 found in man. 



Colubrine Venom — Naja tripudians Merrem. — The experiments of 

 numerous observers show that the effects of this venom on animals 

 are : — 



1. Paralysis of voluntary movement. 



2. Salivation. 



3. Marked effect on the respiration, which ceases before the heart. 

 In smaller quantities the paralysis becomes more marked, and 



in cases of longer duration several features are added : — 



1. Local inflammation where the bite was inflicted. 



2. Lachrymation. 



