The preface to the Herbarius zu Teutsch begins with the words, “Offt und vil habe ich by mir selbst betracht die wundersam werck des schepfers der natuer.” Similar words are found in all the different German editions, and in the later Hortus Sanitatis they are translated into Latin. The preface reveals so clearly and so delightfully the spirit in which the work was undertaken that it seems worth while to translate it almost _in extenso_. It is impossible, however, to grasp the medical ideas characteristic of the earlier herbals, such as those presented in the preface which follows, unless one understands the special terminology, in which the “_four elements_” and the “_four principles_” or “_natures_” play a great part. The ideas expressed by these terms had begun to dominate medical and physiological notions five or six hundred years before the birth of Christ, and they held their own for a period of more than two thousand years. As an instance of their constant occurrence in literature we may recall Sir Toby’s remark in ‘Twelfth Night,’ “Do not our lives consist of the four elements?” In Aristotle’s time these conceptions must have been already quite familiar to his pupils. Like, his predecessors he distinguished four elements, Fire, Water, Earth and Air, and to these he added a fifth—the Ether. In the four elements, the four principles are combined in pairs—fire being characterised by heat and dryness, air by heat and moisture, water by cold and moisture, and earth by cold and dryness. According to Aristotle, heat and cold are active, while dryness and moisture are passive in their nature. By the “temperament” of a man is understood the balance or proportion maintained between these conflicting tendencies. The particular “virtues” of each plant, in other words the power of restoring lost health or “temperament,” are determined by the “principles” which it contains, and the proportions in which these occur. With this introduction we may pass on to the preface of the Herbarius zu Teutsch[5]: