There are various ways in which disease may be avoided. One is not to expose ourselves to contagion or injurious influences. We need to be careful of the food we eat, the water we drink, even the air we breathe, for all of these, as above shown, are prolific sources of the germs of disease, We must also keep away from those afflicted with contagious diseases, or, if obliged to enter their presence, take precautions to avoid infection.

This danger is now taken in hand by the health authorities of cities, patients of this character being removed to special hospitals, or, if kept at home, the yellow placard of warning is conspicuously displayed. Only physicians and nurses who are supposed to know how to take care of themselves—are permitted to enter the sickroom, or even the house in cases of this kind.

A second and highly important method of avoiding disease, whether infectious or from organic weakness, is to strengthen the system by dint of suitable exercises; seek to breathe only fresh and pure air, adapting the clothing to the climate and the bodily needs, and in other ways endeavoring to harden the body and to enable it to defy the insidious assaults of disease.