[Cologne, Printer of Dares (Johannes Solidi (Schilling)), about 1472]. Recently bound in an original handwritten vellum leaf dating from the earlier fifteenth century (containing a fragment of the commentary by the Venerable Beda on the Gospel of St. Luke, chapter XIX, with some lines of music). 16 leaves (complete). Latin text. Full of ligatures and abbreviations. Rubricated and with some decorative initials with simple extensions. Several marginal reader's remarks plus a drawing of a cross, some underlinings. Eleven editions were published between 1467 and 1490. The first was issued in Cologne (1467); this is the fourth, printed anonymously by Johann Schilling - whose name was latinized as Solidi. Excellent condition. 26 copies of this edition in public institutions, none in Belgium or the Netherlands. Goff G197. ISTC ig00197000. 'On the knowledge of chastity and pollutions in the daytime. The form of sacramental absolution'. A short essay, written about 1412, about chastity and involuntary discharge of semen during the day (as opposed to pollutions in sleep, about which Gerson wrote another essay). In Gerson's eyes, both men and women can produce body fluids ('humores') when they are sexually stimulated, even without wanting to. Among other things, it concerns the question of whether a priest is unclean after a pollution and whether he may then still perform sacred acts. A priest who goes to a parishioner on horseback may become excited by the ride and thus come to emission. According to Gerson, this is not a mortal sin, as long as he does not focus on sexual pleasure. He warns against intimate friendships that can lead to sensuality. This in turn may evolve in ‘mollicies’, literally softness in Latin, but understood as self-pleasure or masturbation. On the other hand, in Gerson’s eyes a certain satisfaction about a successful pollution is permitted, because it brings relief. One may pray for physical release while acting as if one did not desire for sexual satisfaction. Gerson has a remarkably light attitude to sexual feelings: don't worry too much and direct your thoughts on other things! Say to yourself: "phy - phy de vobis cogitationes vilissime procul hinc abite in malam horam veneritis sum aliis occupatus" (p. 21). Go away, away, filthiest thoughts, you have come in a bad hour, but I am busy with other things. Wear a cross on your chest or your forehead, it will help. (And one of the early readers of this book has drawn a large cross in the margin to stress the point). Keep yourself from thinking about sex and trust in God. Maybe hypocritical, but a rather practical solution. Thus, a remarkable text, written about 1412 and preserved in several manuscripts as well as eleven printed editions. Johann Schilling’s has been identified as one of the workshops where William Caxton first observed the printing process. A rare and early incunable and a highly interesting text very interesting text about medieval man and the functions of his body, of great historical significance.