MOSQUITOES AND DISEASE 89 



physicians visited certain marshes in Italy where malaria was 

 common and lived there for three months. Mosquitoes are not 

 active by day but are nocturnal in habit. These physicians 

 therefore went about outdoors freely during the daytime, but 

 as evening approached, went indoors, where they were careful 

 to protect themselves from being bitten. Neither of the men 

 was bitten and neither of them contracted the disease, whereas 

 their neighbors who did not protect themselves at night were 

 afflicted with the fever as usual. 



Losses Due to Malaria. It is rather difficult to determine 

 exactly the losses due to malaria. The annual death rate from 

 malaria in the United States is about twelve thousand. There 

 are, however, about three million cases every year, and since the 

 productive capacity of a man suffering from the disease is 

 reduced from fifty to seventy-five per cent, the loss is really 

 appalling. But this does not include everything, for there is a 

 loss to the country rising from the fact that many regions that 

 are excellent for agricultural purposes cannot be developed 

 because of the presence of malaria. After an investigation of 

 this disease in the five states of Louisiana, Mississippi, Alabama, 

 Georgia, and South Carolina, the following report was sub- 

 mitted: 



We must now consider briefly what 635,000 or a million 

 cases of chills and fever in one year mean. It is a self-evident 

 truth that it means well for the physician. But for laboring 

 men it means an immense loss of their time together with the 

 doctors' fees in many instances. If members of their families 

 other than themselves be affected, it may also mean a loss of time 

 together with the doctors' fees. For the employer it means the 

 loss of labor at a time perhaps when it would be of greatest 

 value. If it does not mean the actual loss of labor to the em- 

 ployer, it will mean a loss in the efficiency of his labor. To the 

 farmers it may mean the loss of their crops by want of cultiva- 

 tion. It will always mean the non-cultivation or imperfect 

 cultivation of thousands of acres of valuable land. It means a 



