670 THE POPULAR SCIENCE MONTHLY, 



all its resources insufficient when it strives to reach the heights and 

 penetrate into the depths of the problems of physiology, the element- 

 ary and fundamental truths can be made clear to a child. 



No one can have any difficulty in comprehending the mechanism 

 of circulation or respiration, or the general mode of operation of the 

 organ of vision ; though the unraveling of all the minutiae of these 

 processes may, for the present, baffle the conjoined attacks of the 

 most accomplished physicists, chemists, and mathematicians. To 

 know the anatomy of the human body, with even an approximation 

 to thoroughness, is the work of a life, but as much as is needed for 

 a sound comprehension of elementary physiological truths may be 

 learned in a week. 



A knowledge of the elements of physiology is not only easy of ac- 

 quirement, but it may be made a real and practical acquaintance with 

 the facts, as far as it goes. Tlie subject of study is always at hand in 

 one's self. The principal constituents of the skeleton, and the changes 

 of form of contracting muscles, may bo felt through one's own skin. 

 The beating of one's heart, and its connection with the pulse, may be 

 noted; the iu^uence of the valves of one's own veins may be shown ; 

 the movements of respiration may be observed ; while the wonderful 

 phenomena of sensation afford an endless field for curious and inter- 

 esting 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 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 rela- 

 tions 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 and 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 physiol- 

 ogy 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 reasonable to accuse an advocate of the 

 " three R's" of a desire to make an orator, an author, and a mathema- 

 tician, of everybody. A stumbling reader, a pot-hook writer, and an 



