Copy letter from John Kemsley, Philadelphia, to Peter Collinson ' A Letter from Dr Kemsley to Mr Collinson, concerning the power of Charming attributed (falsely in his opinion) to the Rattlesnake, the Venom of its bite, with several methjods of curing it : also observations on t he medicinal virtues of the flesh of that Viper, on the small Pox and other eruptive fevers : and lastly of the periodical Locusts (rather Cicada) of America. ' Postscript added to letter dated at Philadelphia on 19 March 1735/1736 Read to the Royal Society on 13 May 1736 18 November 1735