X XXII 



of glory which, though not apparent on the surface, must have 

 spurred the Scotchman in his noble ambition. I say that this 

 trait is not obtrusive, and this is true also of other combative 

 and vigorous elements in his character which never for a 

 moment verge on the defect of arrogance, tempered as they 

 are by the most exquisite modesty, a virtue which, I am 

 pleased to think, was fostered in the creóle atmosphere of the 

 time, together with a great love for the land of his birth. 



Though Friday's work is most varied in character, and 

 though it hears throughout the stamp of great originality, it is 

 all thrown in the shade by the great labor and the genial 

 conceptions that he devoted to the problems of yellow fever. 



Though I have often heard him state that his attention 

 and interest were attracted to the subject of yellow fever from 

 the beginning of his career, we find his first contribution to it, 

 to date from 1872 when be began his studies on the alcalinity 

 of the air as the cause of the disease. The American 

 Commission of the National Board of Health for the 

 investigation of Yellow Fever, found him deep in these studies 

 when they visited Havana in 1879. It is evident that the 

 findings of this Commission, in whose work he took great in- 

 terest, greatly influenced Dr. Finlay. The Commission held 

 that yellow fever was an infectious disease, that the germ 

 proceeded from the sick, but that it must undergo some change 

 outside of the body before it became capable of reproducing 

 the infection. It is not difficult to trace in these views one of 

 the several suggestions that awakened in his mind the idea 

 of transmission by a winged insect. He has, himself, given us 

 as another one of these suggestive thoughts, the description of 

 the development of the Puccinia gramminis in the barberry 

 bush as a necessary intermediary host before infecting the 

 corn with rust; a description which he read in van Tieghem's 

 Botany. 



The following year he began to work on his new theory, 

 and in 1881 he enunciated, before the Washington I -onferenee, 

 the memorable propositions that will be found in this volume. 

 Since that date he never ceased in his tenacious endeavor to 

 prove the truth of these propositions. 



From the epidemiologic point of view, and with the 

 arguments of the sister sciences, history, geography, 

 meteorology, zoology; studying the geographic distribution of 

 the stegomyia, and the influence upon this insect of the 

 variations of temperature and atmospheric pressure. 

 demonstrated by most ingenious experiments. Dr. Finlay 



