6o BASIS OF INVESTIGATION. 



besides certain minor parts. The function of the muscle is contract- 

 ability from which we obtain force. The function of the bones is 

 to furnish a support or base upon which the muscles may act. The 

 blood vessels supply material to repair the waste due to functional 

 activity of the muscles ; the nerves convey sensation by which the 

 action of the muscles may be controlled; and the skin serves as a 

 casing to contain the other parts. The nose, an organ not differing 

 very much in size or shape from the finger, has approximately the 

 same proportions of muscle, bone, blood vessels, nerves and skin, 

 but the functional activity of its muscles is vastly less. When we 

 use the finger we use principally its muscles, when we use the nose 

 we use principally its nerves — olfactory nerves. The external 

 human ear, though differing widely from the finger and nose in 

 shape, does not differ much in the amount of material out of which 

 it is formed. It is, however, inert. What function it has is simply 

 that of deflecting sound waves, and this function is not within the 

 control of the individual. 



EFFECT OF EXERCISE. 



If we exercise the fingers continually, as in piano playing, they 

 acquire both strength and flexibility. Strength and flexibility are, 

 therefore, acquired characters arising from use of the muscles of the 

 fingers. If we examine the fingers before and after such acquire- 

 ment, we find that the differences in size and shape are scarcely 

 perceptible. These acquired characters of strength and flexibility 

 give the fingers an increased functional capacity, i. e., an increased 

 ability to perform their natural functions. When we find an indi- 

 vidual with characters which might possibly be ascribed to the 

 results of ancestral use, we find these characters are not necessarily 

 organs of increased size, but organs having an increased functional 



