l80 YELLOW FEVER [CH. 



of bacteria were described as the cause of the disease, but all 

 of them have been shewn to be merely secondary invasions. 



In addition to being regarded as a highly infectious disease, 

 yellow fever was always considered to be contagious, and 

 patients suffering from it were strictly isolated and their cloth- 

 ing, etc. thoroughly sterilized. In spite of this isolation of 

 patients, however, epidemics were not checked, and it was 

 noticed that many persons became infected without ever 

 having come in contact with infected cases, whilst frequently 

 doctors and nurses, who worked in the same rooms as the 

 patients, did not suffer from it. 



It was also observed that ships coming from infected ports 

 frequently carried the infection and consequently quarantine 

 ordinances were brought into force, which to some extent 

 reduced the spread of the disease, but the wars at the end of 

 the eighteenth century caused these measures to be relaxed, 

 with the result that some very serious epidemics occurred 

 about this time. These afforded some opportunities for the 

 study of the disease and several American observers called 

 attention to the large numbers of mosquitoes and other insects 

 that occurred during yellow fever epidemics. In 1848, Nott, 

 of Mobile, accused some insect or mosquito of being the possible 

 carrier. It was not, however, till 1881 that Charles Finlay of 

 Havana definitely attributed the transmission of the disease 

 to a mosquito. He had noticed in Cuba the connection that 

 seemed to exist between the prevalence of yellow fever and 

 the presence of large numbers of the tiger mosquito, 5. fasciata. 

 Accordingly, he attempted to transmit the infection experi- 

 mentally by feeding mosquitoes on patients suffering from the 

 disease and subsequently on normal persons. Although his 

 experiments were open to many objections, there is no doubt 

 that Finlay did succeed in transmitting the disease by means 

 of the bites of mosquitoes and he energetically advanced his 

 theory in a number of articles. Eventually his views began 

 to attract the attention they deserved and finally, in 1899, an 

 American Commission was sent to Cuba to study the disease. 



This commission was composed of four members, Reed, 

 Carroll, Lazear, and Agramonte, and the way in which they 



