90 ON ELEMENTARY INSTRUCTION IN PHYSIOLOGY. [LECT. 



endless field for curious and interesting self -study. 

 The prick of a needle will yield, in a drop of one's 

 own blood, material for microscopic observation of 

 phenomena which lie at the foundation of all biological 

 conceptions ; and a cold, with its concomitant cough- 

 ing and sneezing, may prove the sweet uses of adversity 

 by helping one to a clear conception of what is meant 

 by " reflex action." 



Of course there is a limit to this physiological 

 self-examination. But there is so close a solidarity 

 between ourselves and our poor relations of the animal 

 world, that our inaccessible inward parts may be 

 supplemented by theirs. A comparative anatomist 

 knows that a sheep's heart and lungs, or eye, must not 

 be confounded with those of a man ; but, so far as the 

 comprehension of the elementary facts of the physi- 

 ology of circulation, of respiration, and of vision goes, 

 the one furnishes the needful anatomical data as well 

 as the other. 



Thus, it is quite possible to give instruction in 

 elementary physiology in such a manner as, not only 

 to confer knowledge, which, for the reason I have 

 mentioned, is useful in itself ; but to serve the purposes 

 of a training in accurate observation, and in the 

 methods of reasoning of physical science. But that 

 is an advantage which I mention only incidentally, as 

 the present Conference does not deal with education 

 in the ordinary sense of the word. 



It will not be suspected that I wish to make 

 physiologists of all the world. It would be as reason- 

 able to accuse an advocate of the "three K's" of a 



