544 THE POPULAR SCIENCE MONTHLY 



person, after which the Stegomyia remains infectious for a long period 

 and may be responsible for a series of new cases. These facts were first 

 discovered during the summer of 1900 by a Yellow Fever Commission 

 consisting of Drs. Reed, Carroll, Lazear and Agramonte, of the U. S. 

 Army. Two of these men, Carroll and Lazear, allowed themselves to 

 be bitten by infected mosquitoes, and Lazear died from a severe case 

 of fever thus contracted. 



Little further has since been learned of the etiology of yellow fever, 

 but wonderful strides have been made in the application of these simple 

 facts for its eradication. In Cuba, where the commission conducted 

 their investigations, the first attempts were made, and in 1902 yellow 

 fever had been entirely eliminated in Havana. Other West Indian 

 islands were formerly badly infested with yellow fever, but at the present 

 time there is little more danger from this disease there than in the 

 United States. Eio de Janeiro was once a hot bed for yellow fever, but 

 it too has yielded to the destruction of mosquitoes and the screening of 

 patients, till after a six years' fight, the fever has vanished. Still more 

 remarkable are the results accomplished in the Panama Canal Zone 

 under the direction of Dr. Gorgas. Here the warfare against yellow 

 fever has gone hand in hand with anti-malarial work and the isthmus 

 has been transformed from a veritable death-trap to a condition which 

 compares favorably with that of any region on earth. 



Our own country has suffered from yellow fever in the past, mainly 

 in the south, but extending to southern Illinois in 1878, to Philadelphia 

 in the terrible epidemic of 1793 and even to Boston and into interior 

 New England towns in the earlier days. The last epidemic occurred 

 during the summer of 1905 in New Orleans, where the application of 

 rational methods rapidly checked the spread of the disease and resulted 

 in its complete eradication long before cold weather. The success of 

 this campaign has undoubtedly sounded the death knell of the yellow 

 fever epidemic and panic in the United States, for New Orleans has 

 amply demonstrated what may be accomplished in the control of an 

 epidemic by an efficient group of workers, backed by a sympathetic 

 public and supplied with reasonable funds. 



Eocky Mountain spotted fever, an important human disease which 

 occurs in certain parts of the Eocky Mountain region in the northern 

 United States, has been shown to be insect-borne. In this case the 

 vector is a tick, not a true insect, but a member of the arthropod group 

 Acarina, whose members are so much like insects in many ways that it 

 is hardly necessary to make any distinction in the present discussion. 

 In 1902 Wilson and Chowning suggested that ticks might carry this 

 disease, and four years later Eicketts definitely proved such to be the 

 case. Spotted fever occurs in its most severe form with 70-80 per cent, 

 mortality in western Montana, but extends into several other near-by 



