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SCIENCE 



[N. S. Vol. XXIX. No. 743 



does this moderate muscular activity 

 minister to the health of the body? We 

 can not discuss this at any length here, 

 and to do so would only be to repeat what 

 has been explained over and over again. 

 But we may mention the following as the 

 principal hygienic effects. 



1. Muscular activity affords training to 

 the heart, so that it is not only equal to 

 the emergencies of life, but is also able to 

 withstand the fatigue of moderate pro- 

 longed exertion. No exercise can be en- 

 joyed unless this fundamental condition 

 is satisfied. 



2. Muscular activity relieves vascular 

 congestions in the internal organs by 

 bringing larger quantities of blood to the 

 skin. In doing this it improves the physi- 

 ological condition of the skin, as well as 

 that of deeper organs. 



3. As a result of the deepened and fre- 

 quently quickened respiration all lobes of 

 the lungs are used and the apical lobes 

 rendered less liable to the attacks of 

 disease. 



4. As a further result of the increased 

 breathing movements, as well as of the 

 pumping action of contracting muscles 

 and movements at joints, the flow of 

 lymph along the lymphatics is greatly 

 favored, and this improves the environ- 

 mental condition of all cells of the body. 



5. Muscular activity also affords im- 

 portant training to the heat-regulating 

 mechanism of the body. 



6. Muscular activity exerts a favorable 

 influence upon the digestive processes, 

 promoting proper secretion and absorption 

 and tending to prevent the unhealthful 

 conditions leading to constipation. 



7. Muscular activity is conducive to re- 

 freshing slumber. This is partly because 

 of the maintenance of normal conditions 

 in the body generally and probably, in 

 part, because it is conducive to the health- 

 ful fatigue which facilitates the normal 



relaxation from nervous strain. What- 

 ever may be the physiological explanation 

 of the phenomenon, there can be no ques- 

 tion of its existence and of its hygienic 

 value to the nervous system. 



It is not essential to our purpose that we 

 make a complete list of these favorable 

 physiological effects. Probably the above 

 comprises the more important of them, and 

 before leaving this part of our subject we 

 may point out two things. First: these 

 are all hygienic essentials and most, if not 

 all, of them can be properly secured only 

 by muscular activity. The training of 

 the heart, the maintenance of deepened 

 breathing without depriving the blood of 

 its due charge of carbon dioxide, the favor- 

 able effect on the flow of lymph— for it is 

 an old physiological observation that there 

 is no lymph flow from the limbs when 

 motionless— the favorable effects on diges- 

 tive functions and on slumber, all of these 

 can be secured in no other way than by 

 muscular activity. This means that phys- 

 ical training is an essential in any prop- 

 erly planned course of education and that 

 no school or college is justified on any 

 ground whatsoever in failing to provide 

 properly for this need of its students. 

 Second: all these hygienic effects can be 

 secured by what we have termed "moder- 

 ate" exercise. Not one of them requires 

 the effort involved in training for athletic 

 events. This fact seems to me to justify 

 a statement which I have made elsewhere 

 to the effect that "the athletic ideal is not 

 the hygienic ideal; it may not be unhy- 

 gienic, but it is not required for purposes 

 of health." 



But athletic training and athletic eon- 

 tests may be at least desirable and possibly 

 necessary for other than hygienic pur- 

 poses; and so the question at once pre- 

 sents itself whether in using it for these 

 purposes unjustifiable risks to health are 



