290 PROGRESS OF SCIENCE IN THE CENTURY. 



is lived in nature is an essential part of a general 

 system of Biology. It began in practical lore, at- 

 tained a high degree of excellence in the seventeenth 

 and eighteenth centuries, but acquired in the nine- 

 teenth century greater dignity and definiteness espe- 

 cially through the influence of evolution-doctrine, 



STUDY OF THE FUNCTIONS OF ORGANS. 



Sir John Burdon-Sanderson dates modern physiol- 

 ogy from the work of Johannes Miiller (1801-1858). 

 " Just as there was no true philosophy of living na- 

 ture until Darwin, we may with almost equal truth 

 say that physiology did not exist as a science before 

 Johannes Miiller. For although the sum of his 

 numerous achievements in comparative anatomy and 

 physiology, notwithstanding their extraordinary 

 number and importance, could not be compared for 

 merit and fruitfulness with the one discovery which 

 furnished the key to so many riddles, he, no less 

 than Darwin, by his influence on his successors was 

 the beginner of a new era.* 



Steps of Progress since Johannes Miiller. — What 

 then has been the nature of the steps of progress in 

 regard to the physiology of organs during this 

 period which dates from Miiller ? As it seems to us, 

 the steps may be grouped under four heads: — (1) 

 the partial elucidation of the function of organs pre- 

 viously enigmatical, (2) the recognition that the 

 functions of organs, whose uses were partially known, 

 are much more complex than was previously sup- 

 posed, (3) a fuller understanding of the correlation 

 and co-operation of the various organs in the life of 

 the whole, and (4) the progress made in comparing 

 analogous organs in different kinds of organisms. 

 ♦Pres. Address. Rep. Brit. Ass. for 1893, p. 9. 



