CARL LUDWIG AND CARL THIERSCH. 345 



When, in the course of a few years, the new school of physics in Ber- 

 lin was formed, he entered on a correspondence with its representa- 

 tives — with E. Briicke, E. Du Bois-Reymond, and H. Helmholtz. 

 Ludwig's first opportunity of meeting these somewhat younger 

 friends was in 1847, when he made a short visit to Berlin. It was 

 then that he also made the acquaintance of E. H. Weber and A. 

 Volkmann. He seems to have led Volkmann to the use of his 

 recently invented kymographion, for, as is known by common report, 

 they experimented together for a time. 



In his manner of investigating, Ludwig was all his life a most 

 acute analyzer, seeking with the utmost care to separate every vital 

 process into its various branches, and to determine the conditions of 

 its manifestations. In this work he always attached great importance 

 to the quantitative determination of all the factors of the problem. 

 This manner of work of course often resulted in the questions that he 

 had investigated seeming further from a satisfactory solution than 

 before he had begun; Ludwig, however, never regarded any line of 

 research as definitely closed, but years later returned again and again 

 to work on the problems he had undertaken to solve, and continued 

 his researches with the help of his added knowledge and experience. 

 Herein lay one of the most interesting sides of his richly endowed 

 nature; in his search for the truth he never faltered, but with untir- 

 ing energy continually attacked the problem with new weapons. 



Ludwig's mode of scientific work was entirely opposite to E. H. 

 Weber's. Weber possessed the gift of artistic intuition. He ab- 

 sorbed himself in his problems until he believed that he had mastered 

 the main substance of the matter, after which he was able in a few 

 clear strokes to draw an illustration of oftentimes wonderful sim- 

 plicity. Weber's scheme of the circulation, constructed by the insig- 

 nificant means of a piece of intestine and a few lamp chimneys, 

 solved with one stroke, convincing even to beginners, some of the 

 most abstruse problems of the theory of the circulation, and even the 

 complicated technique of later physiology has not been able to dis- 

 pense with it. The first one to recognize this was Ludwig himself; 

 in fact, he went so far as to consider Weber's discoveries of greater 

 importance even than Harvey's discovery of the circulation of the 

 blood. Intuitive natures, such as Weber's, may make particularly 

 clear teachers. The artistic perception, however, which is their most 

 valuable quality, can not be transferred to others, and thus we seldom 

 find them as founders of any school of science. Thus Weber, if we 

 do not include his personally congenial friends, never in all his long 

 career attracted scientific pupils. Ludwig, on the other hand, made 



works on the circulation of the blood (1832), and Johann Miiller's investigations on the 

 formation of the voice. 



