The health regulations of the Sanitary Department, such as the isolation and care of yellow-fever patients, were thoroughly and carefully carried out. But in spite of all this work and care, yellow fever had been steadily growing worse ever since we had taken possession of the city, and in 1900 there were a greater number of cases than there had been for several years. The Cubans twitted us with the fact that all our cleaning up and expenditure not only had not bettered things, but had even made them worse. They called attention to the fact that the very cleanest and best kept portions of the city were by far the worst sufferers from yellow fever, and the evidence was so staringly before our eyes that we had to acknowledge the truth of what they said. The health authorities were at their wits’ end. We evidently could not get rid of Havana as a focus of infection by any method we then knew. A few years before this period, an Italian savant had announced in Brazil that he had discovered the organism which caused yellow fever. This organism was known as the bacillus icteroides of Sanarelli, and it was quite generally accepted that Sanarelli had proved this to be the causative agent in yellow fever. Drs. Reed and Carroll had proved that the bacillus icteroides of Sanarelli was identical with the hog-cholera bacillus. They made this demonstration while comparing the bacillus X of Sternberg with the bacillus icteroides of Sanarelli. The work was carried on by them during the years 1897 and 1898, at the laboratory of the Army Medical Museum in Washington. The investigation was undertaken at the request of General Sternberg. In 1899 our Public Health Service published the report of a board of medical officers who had been sent to Havana to investigate Sanarelli’s organism. This report made a great impression. Surgeon-General Wyman, in his letter transmitting the report says: The findings of this Commission, verifying the discovery made by Sanarelli, and making still further advances than did Sanarelli himself by determining the specificity of the bacillus icteroides, and that the primary infection of yellow fever is received through the respiratory tract, in other words, verifying one discovery and making others of almost equal importance, at the same time eliminating incorrect theories, must be considered a notable achievement in medical science and one of the greatest practical value to the people of the United States and other countries infected, or liable to be infected by yellow fever. * * * * * In view of the widespread interest which the report will excite and the practical deductions to be drawn therefrom, I have respectfully to request authority to have the same printed. The findings of this Commission were: