Mosquitoes and Yellow Fever 137 



such receptacles and other possible breeding-places 

 for mosquitoes were kept covered. After the first 

 inspection, 4,000 breeding-places were reported. 

 About six months later there were less than 400. 

 Similar work was done in all the towns and settle- 

 ments along the route of the canal. In addition to 

 this fight against the yellow fever mosquito con- 

 siderable attention was paid to the breeding-places 

 of the malarial mosquito. The results have been 

 remarkable. Cases of yellow fever are now rare 

 throughout this zone, and there has been a very 

 great reduction in the extent of the malarial dis- 

 tricts. The last case of yellow fever occurred in 

 May, 1906. Before this work was done a man took 

 his life in his hands when he went into this region. 

 Now it is regarded as a perfectly safe place to live. 

 Indeed it is a much safer place than many sections 

 of our own country where proper sanitary measures 

 have not been taken to protect the health of the 

 community. 



IN RIO DE JANEIRO 



In Rio de Janeiro they have as yet been unable to 

 get rid of the mosquitoes, although thousands of 

 dollars are spent annually in fighting them. But 

 the non-immunes there protect themselves by do- 

 ing their business in Rio during the day and going 

 back at night to Petropolis, twenty-five miles in- 



