DISTRIBUTION OF DISEASE GERMS 



107 



community have flies. It is also to be noted that people who 

 will leave refuse exposed so that flies breed in it are likely 

 to be the kind of people who would allow disease bacteria 

 to get into the refuse, thus making possible their further 

 distribution by flies. If no disease germs were allowed to 

 get into the refuse, the increased number of flies would be 

 annoy ing, but not 

 necessarily of any 

 importance rela- 

 tive to disease. 



123. Cleanliness 

 and disease. In- 

 dividual and civic 

 cleanliness are 

 important. Our 

 standards of taste 

 and of decency 

 should demand 

 that sewage, gar- 

 bage, and all 

 kinds of refuse 

 be removed at 

 proper times and 

 in proper ways. 



But vastly more 



,1 

 important IS the 



care which will 

 insure that disease germs may not be allowed to pass to 

 other people. When, in 1898, the United States took posses- 

 sion of Havana, Cuba, the harbor, naturally one of the finest 

 in the world, was filled with refuse from Havana. In the city 

 open sewers carried bacteria-laden sewage, and flies, mosqui- 

 toes, dogs, and rats had ready access to this filth. During the 

 year 1898 one human being in each twelve died the terrible 

 price that ignorance and carelessness exact. Our army had 



FIG. 54. Bacteria carried by a fly 



A plate of agar culture medium over which a fly was 



allowed to walk. Colonies of bacteria have developed 



where the fly touched the culture medium 



