430 HISTORY OF PHYSIOLOGY. 



real advance in science, there must have been clear 

 ideas and real facts, unity of thought and extent of 

 observation, brought into contact. 



Sect. 2. Recognition of Final Causes in Phy- 

 siology. Galen. 



THERE is one idea which the researches of the 

 physiologist and the anatomist so constantly force 

 upon him, that he cannot help assuming it as one 

 of the guides of his speculations ; I mean, the idea 

 of a purpose, or, as it is called in Aristotelian 

 phrase, a final cause, in the arrangements of the 

 animal frame. It is impossible to doubt that the 

 motive nerves run along the limbs, in order that 

 they may convey to the muscles the impulses of the 

 will; and that the muscles are attached to the 

 bones, in order that they may move and support 

 them. This conviction prevails so steadily among 

 anatomists, that even when the use of any part is 

 altogether unknown, it is still taken for granted 

 that it has some use. The developement of this 

 conviction, of a purpose in the parts of animals, 

 of a function to which each portion of the organiza- 

 tion is subservient, contributed greatly to the pro- 

 gress of physiology; for it constantly urged men 

 forwards in their researches respecting each organ, 

 till some definite view of its purpose was obtained. 

 The assumption of hypothetical final causes in phy- 

 sics may have been, as Bacon asserts it to have 

 been, prejudicial to science ; but the assumption of 



