12 SCIENCE PROGRESS. 



recognised the importance of the principle that vital pheno- 

 mena can only be understood by comparison with their physical 

 counterparts, and foresaw that in this principle the future of 

 Physiology was contained as in a nutshell. Feeling strongly 

 the fruitlessness and unscientific character of the doctrines 

 which were then current, they were eager to discover 

 chemical and physical relations in the processes of life. 

 In Ludwig's intellectual character this eagerness expressed 

 his dominant motive. Notwithstanding that his own re- 

 searches had in many instances proved that there are im- 

 portant functions and processes in the animal organism 

 which have no physical or chemical analogues, he never 

 swerved either from the principle or from the method 

 founded upon it. 



Although Ludwig was strongly influenced by the rapid 

 progress which was being made in scientific discovery at 

 the time that he entered on his career, he derived little from 

 his immediate predecessors in his own science. He is 

 sometimes placed among the pupils of the great Comparative 

 Anatomist and Physiologist, J. Mliller. This, however, is a 

 manifest mistake, for Ludwig did not visit Berlin until 1847, 

 when Miiller was nearly at the end of his career. At that 

 time he had already published researches of the highest 

 value (those on the Mechanism of the Circulation and on the 

 Physiology of the Kidney), and had set forth the line in 

 which he intended to direct his investigations. The only 

 earlier Physiologist with whose work that of Ludwig can 

 be said to be in real continuity was E. H. Weber, whom he 

 succeeded at Leipzig, and strikingly resembled in his way 

 of working. For Weber, Ludwig expressed his veneration 

 more unreservedly than for any other man, excepting per- 

 haps Helmholtz, regarding his researches as the foundation 

 on which he himself desired to build. Of his colleagues at 

 Marburg he was indebted in the first place to the anatomist, 

 Professor Ludwig Fick, in whose department he began his 

 career as Prosector, and to whom he owed facilities without 

 which he could not have carried out his earlier researches ; 

 and in an even higher degree to the great chemist, R. W. 

 Bunsen, from whom he derived that training in the exact 



