_Vincent of Beauvais._--Vincent of Beauvais, France, a Dominican monk who lived during the first half of the thirteenth century and was the tutor of Louis the Ninth’s children, devoted the major part of his time to literary work. He wrote many theological treatises and also edited a large encyclopaedia in which information is furnished regarding everything that was known at that time. Several hundred authors aided him in compiling this work, which is entitled “_Speculum Majus_.” It is arranged in three parts, one of which (“_Speculum Naturale_”) consists of 33 books that are divided into 3740 chapters; and quite a number of the divisions are devoted to topics relating to medicine. The authors, from whose writings this medical information has been abstracted, are Hippocrates, Aristotle, Dioscorides, Haly Abbas, Rhazes, Avicenna and several others--not to mention the Church Fathers and other encyclopaedic writers connected with the Church. The first printed edition of this great work appeared toward the end of the fifteenth century (1473–1475 A. D.); the last, or one of the last, in 1624. Lack of space will not permit me to give any details concerning the works of a somewhat similar character which were prepared, about the same time, by the English Franciscan monk Bartholomaeus of Glanvilla (1260); by the Dominican, Thomas of Cantimpré (1204–1280 A. D.), a pupil of Albertus Magnus; and by others. _Roger Bacon._--Roger Bacon was born about 1210 A. D. in Ilchester, Somersetshire, England, and received his early training at Oxford. When he was thirty years of age he went to Paris and, after devoting himself assiduously for seven years to the study of various branches of learning, he received the Doctor’s degree (1247). The wish to acquire a thorough knowledge of whatever subject he undertook to study constituted a prominent feature of his character. He was fond of languages, but he had an even greater love for mathematics, particularly in connection with astronomy, and for experimental work in the department of chemistry. It is said that he expended a large sum of money (£2000) upon these chemical investigations. He left Paris in 1250, returned to England, and not long afterward joined the Order of the Franciscans. Robert Grossetête, Bishop of Lincoln, and the Franciscan monk Adam of Marisco--two men whom Neuburger describes as theologians of a very liberal type--exercised a strong influence upon Bacon at this period of his life. They confirmed him in the belief that familiarity with the learned languages was an acquisition greatly to be prized, and at the same time they gave him every encouragement to pursue his researches in mathematics and in natural history. For a certain length of time he was an instructor at Oxford, but his views with regard to ecclesiastic and moral questions and the discoveries which he made in physics (especially in optics) were beyond the comprehension of his contemporaries, who did not hesitate to