hand, began his presentation with a Physiology of Atoms and of Conditions of Aggregation. As an ideal form of investigation, he conceived the possibility of deducing the functions of complicated molecules from the conditions of their elementary construction, thence, however, to continue step by step to the tissues, and subsequently to the organs. Thus he thought to construct an intelligible theory proceeding from the simple to the complex, and at the same time to determine with mathematical accuracy the derivation of the one from the other in respect to direction, time, and quantity, and to prove the existence of each as the necessary outcome of a natural law.
The theoretical need of an elementary foundation for physiology caused Ludwig in his earlier years to study certain fundamental physical processes, such as filtration, diffusion, and the laws of hydraulics, with especial attention, and to make use of the knowledge thus obtained to explain the phenomena of animal life. Later he grew far more cautious as regards these explanatory experiments, and references to the organic connections of vital processes are much more frequent in his later work. He now speaks with especial predilection of the wonderful mechanism of life, the intricate workings of which, in all its complications, it is the duty of science to reveal.
I here quote a few words from the speech that Ludwig delivered on entering on his professorship at this university: "Physiology," he said, "has entered with full consciousness the sphere of mechanics, where rigorous laws obtain, and where the inexorable logic of circumstances rules the course of the atoms; but we, the heavily burdened servants of science, have armed ourselves with a thousand weapons with which to pursue the intangible phenomena of Nature, and, reflecting on these, we endeavor to understand the subtle mechanism of life. And when we finally receive our reward, when we at last comprehend an organ in all its connections, our proud consciousness is crushed by the knowledge that the human discoverer is but a bungler beside the unknown creator of animal life. For when man compares himself with him in the solution of any problem, he must ever fall short, as does the telescope compared with the eye, and the litmus paper with the tongue. And if all this was once clear, why must it needs again become obscure to us?"
If, however, we desire to understand Ludwig's full importance, we must seek him in his laboratory, and in the midst of his pupils, for here his most characteristic and noblest qualities reached their fullest development. A summary of Ludwig's and his students' work can only be indicated here. With his endeavor to make the construction of the body physiologically comprehensible, Ludwig, unlike some of his friends who were engaged in the same line of work, did not confine himself merely to physical experiments, but
