ENTRY OF THE VENOM INTO THE BODY 263 



Thus, Mitchell and Reichert long ago showed that muscle-fibres 

 at the site of the bite were quickly softened by crotalus-venom, 

 and Flexner and Noguchi have shown that gelatin is liquefied by 

 both crotalus- and cobra-venoms, but that coagulated proteids are 

 not acted upon. Microscopically the muscular fibres at the site 

 of the bite are seen to have undergone necrosis and degenera- 

 tion, and later a polymorphonuclear leucocytic infiltration may be 

 noted. 



9. Cardiac and Vascular Tonic— Sir Lauder Brunton and Sir 

 Joseph Fayrer showed that the poisons of the cobra had a stimulant 

 effect on the heart, and that the circulation could be kept going 

 for a long time after complete failure of breathing if artificial 

 respiration is kept up— a fact of considerable importance if any 

 antidotal treatment is available. 



It is not clear whether this is due to direct action on the muscles 

 of the heart, but it appears from Rogers' experiments that the 

 .effect on the bloodvessels is due to local action on the arterioles. 

 This effect is produced by the cobra and Vipera russellii venom. 



Entry of the Venom into the Body. 



The poison, the characters of which have been described, is intro- 

 duced into the body of man or that of an animal usually by the 

 snake biting the skin and injecting the poison either subcutaneously 

 or into a vessel. In the former case it will soon reach the blood- 

 stream, and be distributed to the different parts of the body. 



The effect of entry into a bloodvessel is to produce immediately 

 the signs of the poisoning, whereas in the subcutaneous tissue it 

 may take some time, and even be modified, especially in the viperine 

 type. 



The quantity injected by a cobra, according to Acton and 

 Knowles, during the first strike, is 0-172 gramme {i.e., }f of total 

 venom in gland); during the second 0-1215; after which it steadily 

 diminishes until it is not fatal to man (probably) about the seventh 

 or eighth strike. Echis injects of total venom during first 

 strike. 



If the venom falls on the conjunctiva it is readily absorbed, and 

 symptoms of poisoning will ensue, or an acute inflammation be 

 set up. 



Taken by the mouth, the venom of the colubridae is harmless, 

 provided there are no cracks or abrasions, and is destroyed by the 

 saliva and pancreatic juice. Viperine venom, on the other hand, 

 causes gastritis, gastro-intestinal haemorrhage, and even death, 

 without the appearance of the usual symptoms, a fact known to 

 the natives of Ceylon with regard to the venom of Vipera russellii. 



Minimum Lethal Dose (M.L.D.). 



The minimum lethal dose varies with the species of snake, the 

 condition of the snake, and with the species of the victim- 



