THE STUDY OF STRUCTURE. 337 



Although Johannes Miiller was probably greatest 

 as a physiologist, he touched and influenced every 

 department of biology, and his touch was that of 

 genius. Even if he had left no record behind him 

 but his work in comparative anatomy, his place on 

 the roll of honour would be high. And apart from 

 actual work, it should be recalled that Virchow, 

 Kb'lliker, Gegenbaur, Haeckel, Briicke, Giinther, and 

 Helmholtz were among his pupils. 



Sir Eichard Owen (1804-1892) links Cuvier, at 

 whose feet he sat for a short time, to Gegenbaur and 

 Huxley, excelling Cuvier in the accuracy of his work 

 and in the generalising spirit which he brought to 

 bear upon his problems, but occupying a strange 

 midway position, on the one hand, extremely con- 

 servative and unappreciative of Darwinism; on the 

 other hand, really believing in the derivation of 

 species from one another. 



Of the work of Owen and others we have else- 

 where given a brief sketch,* and must be content 

 here to emphasise the importance of the service which 

 he rendered to morphology by his clear distinction 

 between homologous and analogous organs. 



Organs which resemble one another in essential 

 structure and in development are called homologous; 

 organs which resemble one another in the function 

 they perform are called analogous, (a) Thus the 

 wing of a flying bird is homologous with the arm of 

 man ; there is a fundamental similarity in the bones, 

 muscles, nerves, and blood-vessels; they have also 

 the same mode of development; both are true fore- 

 limbs, but they are not analogous, for men do not 

 fly, nor do birds grip with their fingers. (&) The 



* Science of Life, 1899. 



