Processus integri in morbis ferè omnibus curandis
A 1693 London medical treatise by the physician Thomas Sydenham, published for the general medical reader of its day and held by the Wellcome Library. Its two pictures are not illustrations but stains: large irregular brown blotches of foxing and water damage spread across the cream paper, one with a dark sharp-edged tail and one with a pair of thin diagonal streaks. A designer might take from them an authentic aged-paper texture for backgrounds, overlays or distressed effects.
