From a practical standpoint though I am inclined to think that the yellow-fever question is settled. The discovery that it is the mosquito alone that conveys the disease will enable us to manage it. I cannot but think that the freedom of Havana from yellow fever on the 24th of August, a thing never before known, must be due to the fact that we got the infected mosquito nearly every time. The disease has been introduced freely from the outside, and yet has not spread among our thirty thousand non-immunes. I believe that our system gets them nearly every time. I think we will soon have Santiago de las Vegas under control. We are inspecting and keeping track of all the non-immune travelers coming to Havana. They are seen by one of our doctors every three days of their stay in Havana, up to six. We have gotten hold of several in this way, and the town is being regularly gone over with the same system that we have in Havana. We had a case on the 20th from Las Vegas, but it was from a part of that town that had not been disinfected. I feel confident that we will have no more cases from Las Vegas after September 1st. This will be a very nice demonstration of what can be done by our system of mosquito killing. Heretofore we have disinfected exactly as last year, plus using the pyrethrum powder and oil in the infected house and in all the neighboring houses. Formaline was used in the infected room and the clothing was sent to Las Animas Hospital, and the patient quarantined. I did it because it could not decrease the effectiveness of disinfection, and would relieve me from criticism in case we were not able to control yellow fever, and had as much as we had last year. I must confess that our results this year are entirely unexpected to me, and if I had any idea how they were coming out I might have discontinued the disinfection of clothing long ago. But in order that the cases may be reported as generally as possible, I am doing everything that I think I safely can to make the routine as little burdensome to the people, as possible. In accordance with this, I have this month issued an order that in yellow-fever cases the only disinfection was to be with pyrethrum; that the clothing was not to be taken to Las Animas, and that after the fifth day the patients were not to be quarantined or screened. I have been designated by the Military Governor to represent the Department at the Public Health Association next month at Buffalo, and also the Board of Health at the meeting at Niagara which is scheduled to occur on the 13th. I hope to see you there if I go. If things are as quiet as they are now, I will probably go; but if I have any yellow fever on hand I would rather send somebody else.