THE UNITY OF SCIENCE. 



THE COEKELATIOISr OF KNOWLEDGE. 



Verworn speaks of Johannes Miiller (1801-1858) 

 as " one of those monumental figures that the history 

 of every science brings forth but once. They change 

 the whole aspect of the field in which they work, and 

 all later growth is influenced by their labours." When 

 we enquire into the secret of Miiller's achievements, 

 we find that he combined genius with unsurpassed 

 working-power, but it is important to notice more 

 definitely what we may call his sense of the correla- 

 tion of knowledge. " He did not recognise one 

 physiological method alone, but employed boldly 

 every mode of treatment that the problem of the 

 moment demanded. Physical, chemical, anatomical, 

 zoological, microscopic and embryological knowledge 

 and methods equally were at his disposal, and he 

 employed all of these whenever it was necessary for 

 the accomplishment of his- purpose at the time." * 



If we take Pasteur (1822-1895) as another repre- 

 sentative figure in nineteenth century science, we may 

 * Max Vevworn, General Physiology, trans. 1899, p. 20. 



