Comprising Descriptions of All the Officinal Peruvian Barks Including Several New Species ; Baron de Humboldt's Account of the Cinchona Forests of South America, and Laubert's Memoir on the Different Species of Quinquina ; to which are Added Several Dissertations of Don Hippolito Ruiz on Various Medicinal Plants of South America ; with Several Plates ; and a Short Account of the Spikenard of the Ancients, with a Plate