THE POISONOUS ^NAKES OP INDIA. 101 



the blood. This in itself does not account for the transudation 

 that occurs ; but the fact that the lining membrane of the walls 

 of the blood vessels themselves are damaged by another toxic 

 element (haemorrhagin) renders them more permeable. The 

 effects of these two toxins is seen in the great tendency to 

 heemorrhages which are characteristic of the Viperine class of 

 poisons. These haemorrhages may be visible or invisible, and the 

 whole case reminds one forcibly of scurvy, or purpura, diseases 

 mainly characterised by similar blood changes. It frequently 

 happens that the fang punctures continue to bleed or discharge 

 bloody serum, or having stopped, bleeding recommences some 

 hours or even days later. There may be bloody discharges from 

 any mucous orifice. Invisible haemorrhages* in the abdomen 

 may cause pain, tenderness, and vomiting recalling to the physi- 

 cian's mind the identical state of affairs one sees in Henoch's pur- 

 pura. Similarly there may be extravasations into joints, or 

 ■other serous cavities which may become painful, and swollen 

 reminding one of another clinical condition, viz., arthritic purpura. 

 Haemorrhages are apt to occur under the skin producing port wine 

 discolourations in the form of spots or patches of various sizes, or 

 they may occur in muscles, and other tissues giving rise to painful 

 and tender swellings. 



Death due to cardiac failure induced by toxins (1) (a), and (4) 

 or later on to exhaustion may occur in from 1 to 14 days, or even 

 longer. 



Daboia Toxemia. 



Daboia poisoning may be taken as the type of Viperine 

 toxaemias. 



Experimentally in animals three forms of toxasmiae are observed. 



It was observed by A. J. Wall, Fayrer, and others experiment- 

 ing on animals that when the dose of poison was large, rapid and 

 violent convulsions were induced resulting in death from asphyxia 

 in a few seconds or minutes. Lamb was the first to correctly 

 interpret these phenomena. He found that daboia venom contains 

 a ferment that coagulates blood. This ferment is only operative 



* These are specially -well exemplified in the cases of Echis poisoning referred 

 to later. 



