The Board then went to work in earnest along lines which seemed calculated to develop the facts in the matter. They started a laboratory at Camp Columbia, the American military station a short distance out of Havana. Here they bred their mosquitoes from eggs procured from Dr. Finlay, and here the first three experimental cases occurred. The first case was severe; the second case was that of Dr. Carroll, a member of the Board, and was well marked, and Dr. Lazear, another member of the Board, died of the disease. Dr. Lazear visited Las Animas Hospital and was bitten by the mosquito on September 13, 1900; was taken sick September 18th and died September 25th. Previously on August 16th, he had been experimentally bitten by a mosquito which had ten days before bitten a yellow-fever patient in the fifth day of the disease. We know now that ten days is too short a time for incubation in the mosquito, and the fifth day a period too late for the yellow-fever patient to be infectious. Dr. Carroll was intentionally bitten. Dr. Lazear told me after he was taken sick, and a day or two before he died, that he recalled being bitten by a stegomyia three or four days before he was taken sick, and while he was at work at Las Animas, our yellow-fever hospital in Havana. He said that he had noticed the mosquito enough to recognize that it was a stegomyia, and had allowed it to fill and fly away without disturbing it. These three cases satisfied the Board that the stegomyia mosquito was the means of conveying yellow fever, but they determined that they would make such a demonstration of the matter that there could be no doubt in the mind of any reasonable person as to what had been proved.