BACTERIA . 25 
Of course, the disease germs which grow in the in¬ 
terior of our bodies flourish best under conditions of 
darkness and lessened air supply. Out-of-door life, 
then, is a preventive measure, and next to this is a 
FIG. 15. SUNSHINE AS A DISINFECTANT. (After Lefar.) 
Under the letters of black paper there was growth; in the remainder 
of the plate the sunlight killed the bacteria. 
generous supply of sunlight and fresh air inside our 
houses. 
Experiments have shown that the disease germs 
Disease 
and 
Darkness 
