HEALTH AND WELL-BEING 61 



thin film of crude petroleum, the mosquito larvae are 

 smothered, and the numbers of mosquitoes in any locality 

 during a season is materially lessened. 



While the common mosquito culex is a great annoyance, 

 the malarial mosquito anopheles (a-noi'-e-les) is a direct 

 menace to health. (See page 39.) The discovery of the 

 germ of malaria in 1880, and of the existence of malarial 

 germs within the body of the mosquito as its host, with 

 , reasons for the belief that without the mosquito as an inter- 

 mediary there would be no transmission of malaria from per- 

 son to person, forms a wonderfully interesting story. When 

 a malarial germ once finds entrance into the blood of a person, 

 it lives and subdivides within some red blood corpuscle. 

 After a period of a few days the corpuscle is broken down, 

 and the multiplied germs are set free in the blood to enter 

 other red corpuscles where further multiplication occurs. 

 The characteristic chill of malaria usually follows these 

 periodic liberations of the malarial germs in the blood. 



One of the problems of a city administration is the removal 

 of garbage economically and efficiently. The value of the 

 waste in the garbage of a large city, including various metals, 

 old rubber, cloth, glass, and grease, aggregates great sums 

 annually. Destruction of garbage by fire removes the 

 menace to health from any disease germs present in it. The 

 sewage of a great city represents an enormous loss annually 

 in fertilizer for soils. Sanitary conditions, however, and the 

 cost of transportation of this material to places where it 

 could be used, make any prevention of this economic waste 

 largely out of question. 



Rats have long been regarded as a pest, but have been 

 tolerated. The waste caused every year by their depreda- 

 tions on farms, in warehouses, in dwellings, on shipboard 

 and elsewhere is enormous. Since their agency in the spread 

 of the dread bubonic plague has been established, active 



