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VENOMOUS ANIMALS 



Weir Mitchell and others have carefully collected the symptoms 

 following this bite. In most instances the bite is painful, and 

 the part becomes swollen and discoloured, while both the pain 

 and the swelling increase steadily. The swelling is due to the 

 effusion of blood. Very seldom is there any lymphangitis or 

 enlargement of the lymphatic glands. Vesication, sloughing, and 

 gangrene may result if life is prolonged and the dose considerable. 

 If, on the other hand, the amount of poison injected is inconsider- 

 able, the swelling declines, and the pain disappears very quickly. 

 Constitutional symptoms are said by some people to begin directly 

 after the bite, but this is hardly likely, as man is a relatively large 

 animal. Under exceptional circumstances it is recorded that the 

 symptoms did not begin till about thirty minutes after the bite, 

 but usually the length of time is only a few minutes. The person 

 feels extremely faint, or complains that his lower limbs are not 

 able to support him. There is no primary stimulating effect like 

 that mentioned in other venoms. The patient staggers or falls, 

 cold sweats bathe the surface of the skin, and nausea and vomiting 

 occur. The pulse is rapid and feeble, the expression anxious, and, 

 according to Mitchell, in a few cases the mind may be slightly dis- 

 turbed, but this may be largely due to fear. If the patient does 

 not die at this stage, the local symptoms mentioned above become 

 very pronounced, and signs of general blood-poisoning show them- 

 selves, and often lead to death. 



The post-mortem reveals that the brain is normal, but congested 

 and somewhat oedematous; the trachea and bronchi are congested, 

 and full of red frothy mucus.; while the lungs are healthy, but 

 somewhat congested. The peritoneum may contain a little fluid, 

 and the mucosa of the stomach and small intestines may be in- 

 tensely congested and infiltrated with serum. In some cases the 

 blood is coagulated, in some it is fluid. The local swelling is due 

 to serous exudation. The chief features of the post-mortem are 

 vaso-dilatation of the portal system and fluidity of the blood. 



Lachesis. — This snake shows the same symptoms as Crotalus, but 

 it has some effect upon the respiratory centre, causing quickening 

 of respiration before the slowing begins. The phrenics are not 

 paralyzed. Moreover, it is possible that the first quick fall of 

 blood-pressure observed is due to action of the poison on the heart, 

 but the subsequent steady fall is due to the action on the vasomotor 

 centres, as in Crotalus. 



Kitajima says that the region of the bite becomes dark purple 

 in colour and swells ; that the pain is severe and burning ; and that 

 the lymph glands become enlarged and tender. The face is pale, 

 the pulse feeble and rapid. Respiration is normal; a slight fever 

 is not infrequent. Coldness of the extremities, with dyspnoea and 

 cold sweats, come on just before death. Blood has been observed 

 in the urine and faeces. 



