Sentence:  The excellence of alkaline salts, as antidotes to the venom of serpents, has long been established. The "volatile alkali" is a common remedy in India for the bite of the cobra copella and viper, &c. The poison of the <WSD>moccasin</WSD> and rattlesnake is immediately counteracted by the application of this remedy. 
Meaning of the word marked with <WSD> tags:  Any of several North American snakes of the genus "Agkistrodon", "particularly" the copperhead ("Agkistrodon contortrix") and the cottonmouth or water moccasin ("Agkistrodon piscivorus").