Abstract
Stephanus Bisius (1724-1790) was a physician of Italian descent and a graduate of the University of Pavia. He was invited to the Polish-Lithuanian Commonwealth in the early 1760s and became head of the Faculty of Medicine at Vilnius University in 1781. In 1772, Bisius had authored the first original study on nervous and mental diseases in the Grand Duchy of Lithuania. In his 35-page booklet, written in Latin and Polish, Bisius characterized mania and melancholy as diseases of the brain, explaining that the organs that feed the human soul are affected, not the soul itself. He introduced the principles of humoralism and solidism to readers, and recognized that autopsies had failed to reveal reliable findings concerning mania or melancholy. Bisius also described the origins of the challenging disorder called plica polonica, a strange condition associated with tufts of matted hair. As a physician during the medical Enlightenment, Bisius criticized metaphysical speculations in medicine and stated that plica was only a result of superstitions. Even though he proposed antiphlogistic treatments for patients with mania and melancholy, he maintained that time and faith in God might help some patients overcome their infirmities.
