SNAKES OF CEYLON. 539 



echides, one died in 1 hour and 42 minutes, thirty- one died 

 between 2 and 12 J hours, two in 44 hours, and two survived. 

 Dr. Imlach, speaking of Shikarpur, where echides are very 

 abundant, estimated that about 20 per cent, of the snake-bitten 

 cases died. Later, Vidal, speaking of Ratnagiri, where the saw- 

 scaled viper is incredibly numerous, estimated that about 20 

 per cent, of echis casualties proved fatal. Acton and Knowles 

 think that about 40 per cent, of bitten subjects recover without 

 treatment. 



(?) Toxins — 



(1) Toxins operating on nerve cells : 



(a) A depressor acting on and paralysing the vasomotor 



centre (?) (Fraser and Gunn (?) ). 



(b) A depressor to nerve cells generally (Lamb and 



Martin), but insufficient to cause paralysis other 

 than that of the vasomotor centre. 



(2) Agents affecting the constitution of the blood : 



(a) An anti-clotting ferment (Fraser and Gunn). 



(b) " Hemolysin," destructive to red blood cells 

 (Fraser and Gunn). 



(3) " Hsemorrhagin " damaging the lining membrane of 



blood vessels, is probably present. 



(4) A depressor to cardiac muscle (Fraser and Gunn). 



(k) Analysis of the Action of the Toxins — 



(1) (a) A depressor to the vasomotor centre is probably 

 present to explain the reduced blood pressure and 

 cardiac weakness noted by Fraser and Gunn. The 

 same phenomena are seen in daboia poisoning, 

 which, Rogers demonstrated, were due to a paralysis 

 of the vasomotor centre, early death from heart 

 failure ensuing. 



(6) This toxic element accounts for the great depression 

 of vitality seen in echis poisoning. It is insufficient 

 to cause paralysis. 

 74 6(6)20 



