SNAKES OF CEYLON. 481 



the yield is very variable, and for fifty cobras, varying in length 

 from 2 feet 10 inches to 5 feet 10 inches, ranged between 30 -2 

 and 881 # 4 mgms. of desiccated poison. Further, that one 

 snake, 4 feet 4 inches in length, furnished only 30*2 mgms., 

 whilst a young one only 2 feet 10 inches in length furnished 

 31 mgms. Again, one cobra 4 feet 10 inches in length yielded 

 143*4 mgms., whilst another of exactly similar proportions 

 yielded 706 -6 mgms. The average yield for these fifty cobras 

 was 317 mgms. 



(d) Amount injected at one Bite : Acton and Knowles 

 estimate that the average discharge of venom at a bite is 

 about 211 mgms. The variability of the amount injected 

 is exemplified by many experiments on rats. Thus, no 

 less than six rats bitten by cobras, varying in length from 

 2 feet 10 inches to 4 feet 8 inches, did not die as a 

 result. 



(e) Toxicity : Lamb has shown that even the dried product 

 varies in its degree of toxicity, as he found the minimal 

 lethal dose for rats was -07 mgms. with one sample, and --04 

 with another. Again* in Acton and Knowles' experiments, 

 they injected 2 mgms. of poison into fifty rats. As a result 

 all succumbed, but where one died in 53 minutes, another 

 did not die for 20 hours ! 



(/) Rapidity of Absorption : Blake found that a poison 

 injected into the jugular vein reached the pulmonary circula- 

 tion 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. 



