During the past four months (from July to November, 1918), I have been engaged at Guayaquil, Ecuador, under the auspices of the International Health Board of the Rockefeller Foundation, in the study of the etiology of the yellow fever prevalent there. I wish at this time to record briefly some of the more significant results of this study, pending the fuller publication of the details which will follow.
In the later paper acknowledgment will be made of the cordial and indispensable official and professional cooperation of the National and Municipal Health authorities in Guayaquil, especially that of Dr. W. Pareja, the director of the Yellow Fever Hospital, and Dr. León Becerra, director-general of the health department of Ecuador.
In six out of twenty-seven cases studied, the injection into guinea-pigs of the blood of yellow fever patients, after a period of incubation, induced in these animals first a rise of temperature