Jetzer, Johann, a religious fanatic, a tailor by trade, who lived in the early part of the 16th century, was a lay brother of the Dominican convent at Berne. The order to which he belonged about this time were engaged in a controversy with the Franciscans on the doctrine of the immaculate conception. Some noted monks and priests of the former had so fiercely assailed it that they had been summoned to Rome to answer for their conduct. The Dominicans of Wimpfen thereupon determined to appear to one of their novitiates at Berne — this very Jetzer — at midnight, and, representing departed spirits, assured him that in the other world the doctrine of immaculate conception was denied, and that those who had in this world persecuted the opponents of the doctrine were still in Purgatory, and there expiating their crime. He at first was completely duped, and created a great excitement among the masses, which was all that the monks had desired in order to secure the liberation of their comrades at Rome. But when Jetzer found that he had been imposed upon, he seriously opposed the plot at the danger of his life. For further particulars, see Mosheim, Eccles. Hist. book 4, cent. 16, sec. 1, ch. 1, § 12. SEE BERNE CONFERENCE.