MOSQUITOES AND YELLOW FEVER. 19 



Physicians have been theorizing about the cause of yellow fever 

 from the time when the}' began to treat it. It was thought by many 

 that it was carried in the air; by others that it was conveyed by the 

 clothing, bedding, or other articles which had come in contact with a 

 yellow-fever patient. There were one or two early suggestions of the 

 agency of mosquitoes, but practically no attention was paid to them, 

 and they have been resurrected and considered significant onh' since 

 the beginning of the present century, "With the discovery of the 

 agency of micro-organisms in the causation of disease, a search soon 

 began for some causative germ. Many micro-organisms Avere found 

 in the course of the autopsies, and many claims were put forth by 

 investigators. All of these, however, were virtually set at rest by 

 Sternberg in his " Eeport on the Etiology and Prevention of Yellow 

 Fever." published in 1890. but a claim made b}' Sanarelli in June, 

 1897. for a bacillus which he called Bacillus icteroides received con- 

 siderable credence, and in 1899 it was accepted in full by "Wasden and 

 Geddings, of the United States Marine-Hospital Service, who re- 

 ported that they had found this bacillus in thirteen or fourteen cases 

 of yellow fever in the city of Havana. There is no evidence, how- 

 ever, that this bacillus has anything to do with j^ellow fever. In 1881 

 Finlay, of Havana, proposed the theory that yellow fever, whatever 

 its cause may be, is conveyed by means of Culex (now Stegoinyia) 

 fasciatKs (now calopiis). Subsequently he published several im- 

 jDortant papers, in which his views were modified from time to time, 

 and in the course of which he mentioned experiments with 100 indi- 

 viduals, producing 3 cases of mild fever. Xone of the cases, however, 

 was under his full control, and the possibility of other methods of 

 contracting the disease was not excluded. Therefore, his theory, 

 while it was received with interest, was not considered to be proved. 



In 1890 came the beginning of the true demonstration. An army 

 board was appointed by Surgeon-General Sternberg for the purpose 

 of investigating the acute infectious diseases prevailing in the island 

 of Cuba. The result achieved by this board, consisting of Reed, 

 Carroll, Lazear, and Agramonte, was a demonstration that yellow 

 fever is carried by Stegomyia calopus^ and their ultimate demonstra- 

 tion Avas so perfect as to silence practically all expert opposition. The 

 Third International Sanitary Convention of the American Republics 

 unanimously accepted the conclusion that yellow feA'er is carried by 

 this mosquito, and that the Stegomyia constitutes the only known 

 means by Avhich the disease is spread. To-day, after abundant addi- 

 tional demonstration, the original contention of Reed, Carroll, and 

 Agramonte (Lazear having died in the course of the experiments) is 

 a part of the accepted knowledge of the medical world. The im- 

 portance of the discovery can not be overestimated, and its first 

 demonstration was followed by antimosquito measures in the city 



