Discussing the consumption and reception of coffee from Britain to Turkey, Knoll dismissed criticisms of coffee, including that it reduced beauty and virility, or that it was contrary to Islam, instead promoting the merits of the drink. He recommended the medicinal use of coffee for treatment of migraines, deafness, and scurvy, its benefits being derived supposedly from being both acidic and alkaline. Digital facsimile from Google Books at this link. Knoll's pamphlet was also published in French by the same publisher in the same year as Lettre à un ami sur les operations du caffé.