"The attempts made to analyse vegetable substances previous to 1720, merely produced their resolution into the supposed elements of the chemists of those days, namely, salts, Earths, phlegm, and sulphur. Boerhaave and Newmann attempted an examination by fluid menstrua, which was pursued with some success by Rouelle, Macquer and Lewis. Scheele, between 1770 and 1780, pointed out several new vegetable acids."