100 THE POISONOUS SNAKES OF INDIA. 



Daboia poisoning. It is not sufficient to produce 

 paralysis. 



(2) (a) In large doses blood clots firmly within the vessels, and 



convulsions ending in death occur almost imme- 

 diately. The Daboia cannot inject sufficient venom 

 into the human subject to bring about this effect, 

 which is only seen in relatively small animals 

 injected with very large doses. 



(b) In moderate doses a contrary effect is produced in the 



blood, and this, in conjunction with (3) accounts, 

 for the haemorrhages which so frequently occur. 



(c) " Hsemolysin ^' is potent in this venom and still further 



lowers the general vitality induced by 1 (V). It. 

 also has some effect in embarrassing the respiration. 



(d) Reduces the normal resistance to microbic invasion. 



(3) " HaBmorrhagin " by damaging the lining membrane of 

 the arterioles favours leakage of the vessel contents. In conjunc- 

 tion with 2 (b) haemorrhages are frequently the result. 



(4) In conjunction with 1 (a) this causes heart failure. 



(5) A vaso constrictor has been demonstrated by Eogers. By 

 reducing the calibre of the blood vessels, blood pressure would be 

 raised, and the heart reinforced. Any tendency towards such 

 action appears to be nullified by a more potent element operating 

 on the vasomotor centre, via., 1 (a). 



(6) (6) Causes sloughing locally with the formation of an ulcer.. 



The venom is three to five times less potent than cobra venom 

 according to Lamb. 



Its action upon the blood is as follows : — 



A toxic body (haemolj^sin) destroys the red blood cells whose 

 function it is to carry oxygen to the various tissues. As a result 

 all vital processes are lowered. Another toxic principle (antifibrin 

 ferment) very profoundly alters the consistency of the blood, and 

 reduces its clotting powers. The action of this latter principle is 

 exactly that of citric, phosphoric, oxalic and other acids, and is. 

 probably like them due to a precipitation of the calcium salts in 



