Vll 



which we are not now apt to associate together. He was a physicist on 

 the one hand, and an anatomist on the other. At the very time that he 

 was engaged, on his first great discoveries as to the mechanism of the 

 -circulation, it was his official duty, as prosector, to teach medical 

 students in the dissecting- room. Being* no less a master of the new 

 methods which the invention and introduction of the microscope had 

 rendered available, than he was of descriptive anatomy, he was able to 

 approach his great subject — the animal machine and its working — 

 from the physical and. anatomical sides at the same time. That in his 

 iifework the former was the more emphasised, arose from the circum- 

 stance that the advance of physical science had rendered so much 

 possible, that before could not be attempted. There were, however, 

 other circumstances which led him in the same direction ; such, for 

 example, as his intercourse with Bunsen — until 1851 Professor of 

 Chemistry and Physics at Marburg — a man who could not fail to 

 exercise a powerful influence on such a mind as Ludwig's. To him 

 there is reason to believe that he was indebted for that technical 

 knowledge of gas-analysis which in later years was to bear such 

 magnificent fruit. Still greater importance must, I think, be attached 

 to an incident which occurred in 1847, when, in the course of a visit 

 to Berlin, he made acquaintance for the first time with his three life- 

 friends — Helmholtz, Briicke, and clu Bois-Reymoncl. Por it was not 

 Ludwig alone that created modern physiology. It was rather the 

 four friends (in mentioning whom the name of another contemporary 

 —that of Do riders — though he was not one of them, must not be for- 

 gotten), all of whom, as we know from their writings, were of one mind 

 in determining so far as the} 7 were concerned, to throw speculation 

 overboard, and to pursue the methods of the exact sciences in their 

 place. That four such men should be brought together at the very 

 turning point of their several careers, was, indeed, a memorable event 

 in the history of physiology. The time was come for its reunion with 

 the exact sciences, and these were the men who were to effect it. 

 The change would, we may be sure, have eventually been brought about, 

 had these leaders of thought and work not been to the front, but it 

 ■cannot be doubted that its progress would have been retarded. 



The wide range of Ludwig's researches made them more fruitful 

 for the advance of physiological knowledge than those of any of his 

 ■contemporaries. Por although some of the discoveries made, e.g., by 

 Helmholtz* and du Bois-Keymond may have surpassed any of his in 

 brilliancy, neither of these distinguished men could claim to be master 

 of so many subjects in physiology. No one, during so long a period 

 of activity, held in his hands so many threads of investigation without 

 losing hold of any of them or allowing them to interfere with each 



* In the comparison here made between Helmholtz and Ludwig, reference is 

 made exclusively to the physiological work done by the former. 



