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 



Disease 

 and 



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 



