Besides teaching, he produced several medical treatises. One was a massive and widely copied commentary covering the Canon of Medicine by Avicenna. The Nuremberg Chronicle of 1493 referred to him as Subtilissimus rimator verborum Avicenne, "that most subtle investigator of Avicenna's teachings"; the illustration above shows Gentile learning "at the feet of Avicenna."
He is said to have performed the first medical dissection in centuries. Even the Romans, for all their search for knowledge, did not approve of cutting open the deceased. Examining the insides of the human body was necessary for starting to learn how organs work; for example, how liquids flow through the body.
Foligno wrote a commentary on urine and suggested that the blood passes through "porous tubules" (per poros euritides) in the kidneys, which strain it and pass the urine to the bladder. He was also the first to suggest that a fast pulse rate led to higher urine output (as a faster metabolism would). He also believed there was a correlation between the heart and the color of urine. A Journal of Nephrology article says he may have been the first cardionephrologist in history.
He also wrote a popular treatise on the Black Death, and recommended theriac for its treatment. Unfortunately, theriac preparation was complex and time-consuming, so there may not have been enough of it to go around. Not that it would have helped: presumably Foligno would have had access to some; however, he died of the plague at its start, on 18 June 1348.
To cure the plague, you would probably want to know what caused it, and that was a puzzle. Tomorrow I'll tell you of the Paris Consilium, who believed they had the answer.
