Deusing, Herman, son of Anthony Deusing, a distinguished physician, mathematician, and professor, was born in Groningen, March 14, 1654. He was bred to the profession of law, but, taking a dislike to it, he relinquished it, and devoted himself exclusively to theological studies. In 1690 he published his Historia allegorica Veteris et Novi Testamenti, juncta revelatione mysterii s. s. triados. By this work he made himself known as a typical and mystical theologian. The typical interpretation of the Scriptures was pushed to its extreme limits. The doctrine of the Trinity was allegorically explained. The result was, that he was accused of heresy, and debarred from the Lord's Supper. He wrote two works in his own defense, one in Dutch and the other in Latin. In 1700 appeared his Commentarius mysticus in decalogumn et explicatio mystica tum historic de muliere hemorrhoisa etfilia Jairi, tum parabolce de Epulone divite et Lazaro mendico. In 1712 he gave to the world his Mysterium s. s. triados, in which he fully developed his allegorical views of this doctrine. He also contributed several exegetical articles to the Bibliotheca Bremensis. He gradually receded from his extreme views. The Groningen Consistory repealed the sentence of suspension that they had passed against him. He now connected himself with the Walloon Church. He was permitted to spend the remainder of his days in peace, and he died January 3, 1722, in the city of his birth.