THE STUDY OF MUSCLE PHYSIOLOGY. 191 



bine to make the action of the muscle more perfect by over- 

 coming this tendency to imperfect relaxation, which is proba- 



FiG. 179.— Illustrations of the difference in elasticity of inanimate and living matter 

 (after Yeo). 1. Shows graphically behavior of a steel spring under equal' incre- 

 ments of weight. 2. A similar tracing obtained from an India-rubber band. 3. 

 The same from a frog's muscle. Note that the extension decreases with equal in- 

 crements of weight, and that the muscle fails to return to the original position 

 (abscissa) after removal of the weight. 



bly less marked, -independent of these considerations, in the 

 living body. This elasticity of living muscles, which is com- 

 pletely lost on death, is a fair measure of their state of health 

 or organic perfection. Hence that hard (elastic recoil) feeling 

 of the muscles in young and vigorous persons, especially ath- 

 letes, in whom muscle is brought to the highest degree of per- 

 fection. 



This property is then essentially the outcome of vitality, 

 which is in a word the foundation of the differences noted be- 

 tween the elasticity of inorganic and organic bodies. A mus- 

 cle, the nutrition of which is suffering from whatever cause, 

 whether deficient blood-supply, fatigue, or actual disease, is 

 deficient in elasticity. We wish to emphasize these relations, 

 for we consider it very important to avoid regarding vital phe- 

 nomena in the light of physics merely, which the employment 

 of the graphic method (and indeed all methods by which we re- 

 move living things out of their normal relations) fosters. 



Electrical Phenomena of Muscle. —The contraction and 

 probably the resting stage of muscle are attended by the gen- 

 eration of electrical currents, the direction of which is indicated 

 in Fig. 180. 



It will be observed that the diagram indicates that between 

 no current and the strongest obtainable there are all shades oif 



