SNAKES OF CEYLON. 483 



take Lamb's estimate of the lethal dose for man, which is 

 probably nearest the mark, and strike an average for the 25 

 cobras experimented with by Cunningham, Lamb, and 

 Rogers, the average yield of which amounts to 240 mgms, 

 we may state that an average cobra contains poison enough 

 in its glands to kill fifteen men. An exceptional cobra may 

 even contain sufficient poison to kill forty-five men ! Acton 

 and Knowles,by well-reasoned induction and a highly ingenious 

 system of experiment, arrive at the same conclusion as Lamb, 

 and place the lethal dose at 15 mgms. (or -0015 grammes) 

 of dried poison. 



(h) Uncertainty of Effects : When one considers all these 

 facts, viz., the extremely small quantity that constitutes a 

 lethal dose in man, the number of lethal doses of venom 

 available in a normal cobra, and the rapidity of absorption 

 into the blood, it is extremely remarkable that any bitten 

 subject can escape receiving his death warrant however 

 trivial the injuries sustained. In spite of this, it is a well- 

 established fact that a certain number of bitten subjects 

 in which poison too has been indubitably injected do 

 recover, and without treatment. Of course, it is obvious 

 in these cases that the dose absorbed was a sublethal 

 one. 



It seems to me very remarkable how variable are the results 

 of a cobra bite as testified by experiment in the lower animals . 

 Elliot* reports, on the authority of Surgeon-Major Browning, 

 I. M.S., that on one occasion " a healthy cobra bit a dog in two 

 places with no results ; another bite from the same cobra on 

 the same animal resulted in death." Fayrerf records a 

 parallel case. " A mongoose and a full-sized cobra Were put 

 into a large wire cage at I p.m. The snake struck at the 

 mongoose, and they grappled with each other frequently, and 

 apparently the mongoose must have been bitten, as the snake 

 held on to it about the neck and head. The next day at noon 



* Trans. Brit. Med., Assoc. S, Ind, Br., 1895, p. 7. 

 | Thanatophidia, p. 69, 



$7 6(6)20 



