46 THE EIDDLE OF THE UNIVERSE. 



evinced an activity at the Berlin University, as pro- 

 fessor and investigator, which is only comparable 

 with the associated work of Haller and Cuvier. 

 Nearly every one of the great biologists who have 

 taught and worked in Germany for the last sixty 

 years was, directly or indirectly, a pupil of Johannes 

 Miiller. Starting from the anatomy and physiology 

 of man, he soon gathered all the chief groups of the 

 higher and lower animals within his sphere of com- 

 parison. As, moreover, he compared the structure of 

 extinct animals with the living, and the healthy 

 organism with the diseased, aiming at a philosophic 

 grouping of all the phenomena of life, he attained 

 a biological knowledge far in advance of his prede- 

 cessors. 



The most valuable fruit of these comprehensive 

 studies of Johannes Miiller was his Manual of Human 

 Physiology. This classical work contains much more 

 than the title indicates ; it is the sketch of a com- 

 prehensive " comparative biology." It is still unsur- 

 passed in respect of its contents and range of 

 investigation. In particular, we find the methods 

 of observation and experiment applied in it as master- 

 fully as the philosophic processes of induction and 

 deduction. Miiller was originally a vitalist, like all 

 the physiologists of his time. Nevertheless, the 

 current idea of a vital force took a novel form in 

 his speculations, and gradually transformed itself 

 into the very opposite. For he attempted to explain 

 the phenomena of life mechanically in every depart- 

 ment of physiology. His " transfigured " vital force 

 was not above the physical and chemical laws of the 

 rest of nature, but entirely bound up with them. It 

 was, in a word, nothing more than life itself — that is, 



