About the same time an officer of the Public Health Service, Dr. H. R. Carter, was making in Mississippi his epoch-marking observations upon the extrinsic incubation of yellow fever. Measured by the results produced, this was one of the most important papers ever written. Yet as high an authority as the Surgeon-General of the Public Health Service expected the greatest results to flow from the conclusions reached by this Board, and did not notice the report from his subordinate concerning the extrinsic incubation of yellow fever. The conclusions of his Board turned out to be all wrong and useless as to results. The report of Carter turned out to be pure gold, and was one of the great steps in establishing the true method of the transmission of yellow fever. I do not say this in criticism. It is almost impossible for contemporaries to judge the true value of discoveries, or to give the proper position to the men of their own time who make these discoveries. General George M. Sternberg, the then Surgeon-General of the Army, was one of the leading bacteriologists of the profession, and was also one of the best known authorities on yellow fever. He doubted the findings of this Board, and obtained authority from the Secretary of War to appoint a board of Army medical officers to investigate this same subject. He appointed on this now famous and immortal board Reed, Lazear, Carroll and Agramonte. They came to Havana, and spent several months in investigating Sanarelli’s organism. They proved beyond peradventure that it had no causative relation to yellow fever, and identified it as a well-recognized organism. It is an interesting historical fact that one of the yellow-fever patients in whom the Board of Public Health Service found Sanarelli’s organism was a patient of mine. He was a soldier, Private Patrick Smith, Eighth Infantry, a non-immune living in an infected part of Havana, so that I thought that he ought to be reported as a suspect. The case continued nine days, long enough to convince me clinically that the disease was not yellow fever. The symptoms in a case of yellow fever dying on the ninth day are always so well marked that the diagnosis should not be in doubt. But the Board found Sanarelli’s organism, and being themselves convinced that this was the organism of yellow fever, they believed the case to be that disease. It shows the necessity in scientific matters of being on one’s guard, and of approaching investigation with an open mind. The Army Board having satisfied themselves that Sanarelli’s organism bore no relation to yellow fever, but was simply the ordinary hog-cholera bacillus, turned their attention to other matters, though they were always working in relation to yellow fever. They spent a great deal of time in examining the intestinal flora in cases of recognized yellow fever, but could find nothing that seemed to have any relation to this disease in a causative sense.