16 GUSTAV MAGNUS. 



in his research on the gases of the blood (1837) he 

 dealt a blow at the heart of vitalistic theories. He led 

 physics to the centre of organic change, by laying a 

 scientific foundation for a correct theory of respira- 

 tion; a foundation upon which a great number of 

 more recent investigators have built, and which has 

 developed into one of the most important chapters 

 of physiology. 



He cannot be reproached with having had too little 

 confidence in carrying out his principle; but I must 

 confess that I myself and many of my companions 

 formerly thought that Magnus carried his distrust of 

 speculation too far, especially in relation to mathe- 

 matical physics. He had probably never dipped very 

 deep in the latter subject, and that strengthened our 

 doubts. Yet when we look around us from the stand- 

 point which science has now attained, it must be con- 

 fessed that his distrust of the mathematical physics of 

 that date was not unfounded. At that time no separa- 

 tion had been distinctly made as to what was empirical 

 matter of fact, what mere verbal definition, and what 

 only hypothesis. The vague mixture of these ele- 

 ments which formed the basis of calculation was put 

 forth as axioms of metaphysical necessity, and pos- 

 tulated a similar kind of necessity for the results. I 

 need only recall to you the great part which hypo- 

 theses as to the atomic structure of bodies played 



