remarked jokingly that if there was anything in the mosquito theory, I should have a good dose. And so it happened. After having slight premonitory symptoms for two days, I was taken sick on August 31, and on September 1, I was carried to the yellow fever camp. My life was in the balance for three days, and my chart shows that on the fifth, sixth and seventh days my urine contained eighth-tenths and nine-tenths of moist albumin. On the day I was taken sick, August 31, 1900, Dr. Lazear applied the same mosquito, with three others, to another individual who suffered a comparatively mild attack and was well before I had left my bed. It so happened that I was the first person in whom the mosquito was proved to convey the disease. "On the eighteenth of September, five days after I was permitted to leave my bed, Dr. Lazear was stricken, and died in convulsions just one week later, after several days of delirium with black vomit. Such is yellow fever. "He was bitten by a stray mosquito while applying the other insects to a patient in one of the city hospitals. He did not recognize it as a _Stegomyia_, and thought it was a _Culex_. It was permitted to take its fill and he attached no importance to the bite until after he was taken sick, when he related the incident to me. I shall never forget the expression of alarm in his eyes when I last saw him alive in the third or fourth day of his illness. The spasmodic contractions of his diaphragm indicated that black vomit was impending, and he fully appreciated their significance. The dreaded vomit soon appeared. I was too weak to see him again in that condition, and there was nothing that I could do to help him. "Dr. Lazear left a wife and two young children, one of whom he had never seen." These experiments and many others like them conducted on soldiers and Spanish immigrants proved that this particular mosquito would transmit the disease under certain conditions. 1. The mosquito must bite the patient during the first three days of the fever; after that a yellow fever patient cannot infect a mosquito. 2. A period of twelve days must elapse before the mosquito is able to infect another person. After that she may infect anyone she may bite; that is, the germs remain virulent during the rest of the mosquito's life. The French Yellow Fever Commission working in Rio de Janeiro claim that the first generation of offspring from such an infected mosquito is capable of causing the disease after they are fourteen days in the adult condition.