PHYSICAL VIGOR A PROTECTION 279 



becoming more and more common among people at large 

 as well as in armies, and is a wise precaution to all. The 

 protection does not last more than two or three years. 



Physical Vigor a Protection against Contagion 



The best protection against contagion is robust health. 

 A person in strong, vigorous health is much less liable to 

 yield to disease than one less robust. Consequently in 

 the attempt to protect the household from contagious 

 diseases special emphasis should be placed upon methods 

 of increasing the physical vigor of its members. This 

 can be done by wholesome food, by exercise, and by fresh 

 air. An active body is far less liable to disease than one 

 more or less passive. The need of fresh air should be 

 emphasized, perhaps, more than any other point, for the 

 air in houses, for reasons already indicated, is much more 

 liable to be filled with infectious material than the out- 

 door air, and a person who constantly remains in the 

 house is much more liable to yield to contagion. If, 

 however, he is careful to exercise in the open air, he will 

 ward off attacks to which otherwise he might yield. 

 This appKes even more forcibly to the air of our sleeping 

 rooms 'than to that of our living rooms, for fresh air in 

 the sleeping room is one of the greatest desiderata in 

 maintaining good health. The belief that night air is 

 injurious is responsible for much ill health. Sleeping in 

 close rooms without sufficient air causes a general lower- 

 ing of bodily vigor. Our sleeping rooms should have 

 the windows open even in cold weather, and, provided 

 there be mosquito nettings at the windows to keep out 



