1895-96-] Recent Researches on Snake Poison. 201 



of Britain is a lizard, not a snake. It is quite harmless, in 

 spite of the rhyme — 



" ' If I could hear, and you could see, 

 None would live but you and me,' 

 Said the adder to the blind-worm." 



Dumeril and Bibron have divided snakes, from their teeth, 

 into five families: (1) Opoterodonts — teeth in one jaw only; 

 (2) Aglyphodonts — no grooved teeth anywhere ; (3) Opistlio- 

 glyphs — grooved teeth behind; (4) Proteroglyplis — grooved 

 teeth in front ; (5) Solenoglyphs — teeth hollow. The last two 

 contain the poisonous snakes, and it is with them only we have 

 to do. Our British adder belongs to the fifth family, as do 

 also the two common viperjs of India and the rattlesnake of 

 America. The cobra of India, the most common snake in the 

 world, belongs to the fourth family. The two families differ 

 in many ways. Thus — (1) The vipers are viviparous, the 

 cobras oviparous ; (2) the vipers have scaly heads, the cobras 

 shielded heads ; (3) the vipers have a very small upper jaw 

 on a long pedicel, while the cobras have jaws like those of 

 harmless snakes, though the teeth are unlike. 



Notwithstanding these great differences, it was assumed till 

 quite lately that there was only one kind of snake venom. 

 Even Dr Fayrer, in his great book on Indian snakes, makes no 

 distinction of kind in the venom of the two families ; and a 

 recent French writer, M. Calmette, maintains that they are 

 identical in kind, and differ only in degree. This is like a 

 fungologist maintaining that the poison of the Amanita section 

 of Agarics is identical with the poison of the Hyplioloma 

 section, ignoring the researches of Plowright. The first who 

 distinguished cobra venom from viper venom was Dr Wall of 

 Madras : then Dr Norris Wolfenden showed that the two kinds 

 of venom, when analysed, differed in composition, and that the 

 nerves of the man bitten by a cobra remained sensitive to the 

 electric current, which was not the case after viper bite. In 

 America, Dr Weir Mitchell of Philadelphia made a most inter- 

 esting discovery. He dissolved venom in water, and put it in 

 contact with an animal membrane. He found that cobra venom 

 passed through the membrane, while viper venom did not. The 

 first he named venom peptone ; the second, venom globuline. 



This discovery has important practical bearings. You all 



