240 TROPICAL MEDICINE AND HYGIENE 



(a) Effects of Indian Cobra Venom : exemplifying a 

 Typical Elapine Snake. Experimentally, in animals, the 

 usual symptoms of a lethal charge are gradually increas- 

 ing paralysis, beginning with the hind limbs, until the 

 animal lies in a state of drowsiness, with twitchings, and 

 nodding and jerking of the head. Breathing becomes 

 laboured, and at last fails rapidly in gasps, and the animal 

 expires after, perhaps, a few convulsions. After death 

 the heart continues to beat for a time ; the blood may 

 clot well, or slowly and ill ; and there may be, or may not 

 be, dissolution of red blood cells. At the site of injection 

 there is some extravasation and infiltration. In mammals 

 salivation is common. 



In a man bitten by a cobra the effects are much the 

 same, and appear from ten minutes to two hours after 

 the bite is inflicted. Locally there is immediate burning, 

 tingling, and numbness, followed by a certain amount of 

 inflammation, and perhaps by oozing of bloody serum 

 from the punctures. The general symptoms begin with 

 drowsiness, weakness, and unsteadiness on the legs. 

 Soon the victim lies, unable to move, or speak, or swallow, 

 with saliva bubbling from his mouth, and with the pupils 

 usually contracted, though not insensitive to light ; but 

 not entirely unconscious. Nausea and vomiting often 

 occur. The breathing becomes slow and stertorous, and 

 the victim gradually becomes comatose. In a fatal case 

 the coma deepens and the breathing stops, and the pulse, 

 which may have been fairly good, stops soon afterwards. 

 The end has been known to come within an hour of the 

 infliction of the bite, or, on the other hand, not till nearly 

 two days afterwards ; it usually occurs in five to twelve 

 hours. In a happy case the paralysis passes off and the 

 patient rapidly recovers ; in cases that recover, sloughing 

 is restricted to the immediate site of the wound ; there is 

 no deep and extensively spreading destruction of tissue. 



The predominant features in cobra poisoning are : (i) 

 General paralysis, and special paralysis of the breathing 

 mechanism, due to the neurotoxin ; and (2) more or less 

 delay in the onset of the symptoms. 



