ences had been organized in Leipsic, and the ministry of instruction had passed into other hands, Ludwig again confined himself to his own more limited department. His activity in this field, however, soon spread the fame of the Leipsic University throughout the world.
When Ludwig first came to Leipsic he was in the prime of mature manhood, and had already had twenty years of experience in teaching. He had begun his academic career in Marburg, in 1841, where he had been associated with his friend Ludwig Fick as demonstrator in anatomy. In 1849 he went from there to Zurich as professor of anatomy and physiology, and in 1855 he was called to Vienna to the medical military academy, the so-called Josephinum, as professor of physiology.
In 1852, during his stay in Zurich, Ludwig published the first volume of his text-book of Physiology, the second volume of which appeared four years later, when he was in Vienna. Ludwig's Physiology appeared like a meteor on the scientific horizon. It attacked the scientific knowledge of the day, demolishing former theories and conceptions with critical severity, and substituting new ideas and modes of expression which to us, the physicians of that time, seemed extraordinary enough. I well remember the sensations with which I, as an advanced student, on coming from one of Johann Müller's lectures, toiled through Ludwig's recently published work. Much that it contained I could only master by an effort, and much was actually repugnant to me, for it seemed to me to shatter to atoms the most interesting chapters of physiology as it had existed hitherto. And yet, in spite of all inward opposition, I could not resist the overwhelming influence of this powerful book with its vast stores of information, and I had to acknowledge more and more the force of its triumphant method of presentation.
Wherein lay the great step in advance that Ludwig had taken with his Physiology? Ludwig was a pronounced physical physiologist. A physical physiology had, however, existed long before his time. During the preceding two centuries there had already been schools of mechanical therapeutics in which classical works, as those of Borelli on animal movement, of Hales on blood-pressure, had been produced. Beginning in the second decade of this century, the Weber brothers had proved themselves investigators of the first rank, and their fundamental experiments on wave motion, the pulse, human locomotion, on muscular contraction, etc., were founded on a strictly physical basis. Other men of similar ideas, among them A. Volkmann, subsequently joined them. From the time of Lavoisier, works had been coming from France in which physiological questions were treated in a thoroughly physical method—the treatises of Dulong and Despretz on heat production and dissipation, those of Poiseuille
