574 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1921. 



Liceaga and it was not long before all of this was overshadowed by 

 the magnificent results gained by Gorgas in his administration of 

 the sanitary affairs in the building of the Panama Canal. The re- 

 sults of Gorgas's work were to show that the Tropics may be inhab- 

 ited by the white race, a fact of tremendously far reaching importance 

 to the future of the world. 



Unlike Sir Patrick Manson and Sir Ronald Ross, on whom honors 

 have been showered and who are still living to enjoy the fame that 

 has come to them, the three American members of the commission are 

 dead. Lazear succumbed to the fever during the progress of the 

 investigation, Reed not long after, and Carroll a year or so later, 

 both indirectly as the result of their Cuban work. 



Reed died too early to receive the Nobel prize, which probably 

 would have been awarded to him, and I happen to know, from a con- 

 versation with Sir Ronald Ross and Sir Rupert Boyce in Liverpool, 

 in 1905, that Carroll's name was under consideration for this prize 

 just before his death. 



The actual causative organism of yellow fever was not found by 

 the Reed Commission, nor was its development in the mosquito ascer- 

 tained. They found that the blood serum of a patient retained its 

 toxicity after passing through a Birkfeld filter and concluded that 

 the causative organism must be ultramicroscopic. Recently, Nogu- 

 chi, of the Rockefeller Institute, has isolated a spirochaete which he 

 considers to be probably the true cause of the disease and this opinion 

 is shared by Simon Flexner and other prominent pathologists, but 

 the well-known authority on yellow fever, Juan Guiteras, of Habana, 

 has just analyzed the results and shows that there is still some room 

 for doubt. At any rate just what happens to the organism in the 

 body of the mosquito remains to be determined. 



The next most important discovery in this direction related to 

 dengue or breakbone fever, a disease common in semitropical and 

 tropical countries, common in the West Indies, and in the southern 

 United States, and found also in southern Asia, in the Philippines, 

 and in the South Sea Islands, and in the countries about the eastern 

 end of the Mediterranean. In 1902 Doctor Graham, working: in 

 Beirut, Syria, showed that the disease was not contagious in the ab- 

 sence of mosquitoes, but that isolated persons contracted the disease 

 when bitten by mosquitoes which had bitten dengue patients. Later 

 Ashburn and Craig, of the United States Army, working in the 

 Philippines, showed with mosquitoes bred in the laboratories and fed 

 upon dengue patients, that the insects will transmit the disease after 

 a period of three days. The mosquitoes used by Graham in Syria 

 were the cosmopolitan water barrel mosquitoes of the tropics Culex 

 fatigans (now called G. quinquefasciatus), while the yellow fever 

 mosquito, Aedes calopus (or better, aegypti) carries the disease in 



