1619, and there, as we may confidently believe, became acquainted with the botanical doctrines of Cesalpino, who had died fifteen years before. Returning to Germany, he held various professorships during the succeeding ten years in Lübeck and Helmstädt, and became Rector of the Johanneum in Hamburg in 1629. He occupied himself with the philosophy of the day, in which he appeared as an opponent of scholasticism and of Aristotle, and also with various branches of science, mathematics, physics, mineralogy, zoology, and botany. In all these subjects he displayed high powers as a student and a teacher, and especially as a critical observer; in botany at least he was a successful investigator. He was the first in Germany, as Cesalpino had been in Italy, who combined a philosophically educated intellect with exact observation of plants.
His pupils were at first the only persons who profited by his botanical studies, for with his many occupations and a perpetual desire to make his investigations more and more complete he himself published nothing. In 1662 his pupil Martin Fogel printed the 'Doxoscopiae Physicae Minores,' a work of enormous compass left in manuscript at the master's death, and another pupil, Johann Vagetius, the 'Isagoge Phytoscopica,' in 1678. Ray however tells us that a copy of notes on botanical subjects had already reached England in 1660. The 'Doxoscopiae' contains a great number of detached remarks on single plants and on their distinguishing marks, and propositions concerning the methods and principles of botanical research, all in the form of aphorisms which he had from time to time committed to paper. The number and contents of these aphorisms show the earnest attention which he bestowed on the determination of species; he is displeased that so many botanists devote more time and labour to the discovery of new plants, than to referring them carefully and logically to their true genera by means of their specific differences. He was the first who objected to the traditional division of plants into trees and herbs, as not founded on their true nature. But
