it won’t take him long to decide the point. I wanted to come very much, but I have work here which I feel that I should not neglect. Else I should have certainly come down. I have been intending to ask you whether, in dealing with y. f. in Havana, this year, you have confined your work to simply protecting the sick against bites and destruction of mosquitoes; and have _omitted_ all disinfection of bedding and clothing. I sincerely hope that this is true. I shall probably present, with Carroll, a paper to the next meeting of the American Public Health Association on the management and prevention of yellow fever, and I would so like to be able to say that the great work in Havana was accomplished without the disinfection of any bedding or clothing. Carroll leaves New York, with Pvt. Springer, on Ward Line leaving on Wednesday, August 6th. Pardon this lengthy letter. Please present my kindest regards to Mrs. Gorgas. Keep me informed of your progress at S. de las Vegas. Sincerely yours, REED. The parasite has not yet been discovered. Dr. Carroll proved by the experiments which Dr. Reed here refers to that the parasite of yellow fever is sub-microscopic. (8) Havana, Cuba, August 26, 1901. MY DEAR REED: Yours of July 29th received. You will see by the last report that our conditions continue good. So far this month we have had only two cases belonging to Havana, one of these a Cuban child twelve years old who had never been out of Havana. Personally, I have not seen a case since March, belonging to Havana, with which I was perfectly satisfied as being yellow fever, but I am more confirmed in my suspicions since we have had the Santiago de las Vegas cases. You recollect we bit some thirty-four subjects at the time when I last wrote you without being able to transmit the disease in a single instance. These mosquitoes we tried to infect on some dozen of these supposed Havana cases. We all agreed that the Santiago de las Vegas cases were yellow fever. While they were not severe, they were well-marked cases of yellow fever. We bit one man with eleven mosquitoes. He was a well-marked case, but not dangerously ill at any time. These eleven mosquitoes have since bitten seven subjects, six of whom have gone down with yellow fever. Three have recovered and three died. Carroll will no doubt give you details in these cases, and Guiteras will publish the matter in detail. I am very much disappointed. I had hope that through the mosquito we had a means of giving mild cases which would protect, but these cases show that the severest form of yellow fever can be transmitted by one or two mosquito bites. I suppose I ought to be thankful for the immense good that the discovery so far has done, and for the great success that our work this year has had, but the death of these patients, just now, makes all success taste of gall and wormwood, and casts a gloom over the Sanitary Department.