98 ELEMENTARY INSTRUCTION IN PHYSIOLOGY. 



while the wonderful phenomena of sensation afford an 

 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 phenom- 

 ena which lie at the foundation of all biological concep- 

 tions; and a cold, with its concomitant coughing 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 physiology 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 ele- 

 mentary physiology in such a manner as, not only to 

 confer knowledge, which, for the reason I have men- 

 tioned, 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 advan- 

 tage which I mention only incidentally, as the present 

 Conference does not deal with education in the ordi- 

 nary sense of the word. 



It will not be suspected that I wish to make phys- 



