558 JOURNAL, BOMBAY NATURAL HIST. SOCIETY, Vol. XXII. 



however, finding that -25 nigms. is proximately the minimal 

 lethal dose per kilogram weight in monkeys, and poetulating an 

 equal degree of stisceptibility in man, concludes that the dose for a 

 man weighing 10 stone would be about 15 to 17"5 mgms. If we 

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

 nearest the mark and strike an average for the 25 cobras experi- 

 mented 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 15 men. An excep- 

 tional cobra may even contain sufficient poison to kill 45 men ! 



Rapidity of ahsoT][)tion of cobra ijoison. — Blake found that a poison 

 injected into the jugular tein, reached the pulmonary circulation 

 of a dog in from 4 to 6 seconds, and the cardiac circulation in 7 

 seconds. A poison injected into the same vein was distributed 

 throughout the circulation in 9 seconds. It is this extreme rapidity 

 of transmission in the blood stream that accounts for the fatal issue 

 in experiments where a poisoned member is amputated or wound 

 excised almost immediately after being bitten. Russell* caused a 

 cobra after biting a dog twice, to inflict a wound in the leg of a 

 pigeon, and amputated the member one minute later, but the bird 

 died in two hours. On dissecting up the limb the extravasation 

 peculiar to the local action of snake poison was observed half an 

 inch above the punctures and almost reached the point of 

 amputation. 



Fayrer (Expt. 3 of Series 1 Q) caused a cobra to bite a dog in a 

 fold of skin in the groin. The wound was entirely excised " at 

 once," but death took place in 6 minutes. In another experiment 

 (No. 13 of Series 15), the same authority repeated the same perform- 

 ance, the part being " immediately " excised Mdthin 2 seconds. 

 The animal died 2 hours and 35 minutes later. It appears probable 

 that the initial absorption of the poison is far more speedy in the 

 first few seconds (or minutes) than subsequently. (?) 



When one considers all these facts, the extremely small quan- 

 tity 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 tha 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 treaffcment. Of course 

 it is obvious in these cases that the dose absorbed was a sublethal 

 Dne. 



Uncertainty in the effects of cohra hite. — It seems to me very remark- 

 able how variable are the results of a cobra bite as testified by experi- 



* Loc. cit. p. 73. Expt. XXVIII. 



