Rembrandt, ‘The Unconscious Patient (Smell)’, c. 1624, The Leiden Collection, New York. We see an unconscious young man, judging by his closed eyes and pale skin. The two figures beside him are a quack and his assistant. The young man has been subjected to bloodletting, a common treatment for many ailments in the 17th century. He was clearly not supposed to faint during the procedure - the white cloth was probably dipped in smelling salts that release ammonia, to bring him round.