An American machinist, coming from San Francisco to Panama, got off the steamer at Corinto, Nicaragua, got on a spree and was locked up in the Corinto jail. He was left there by the steamer, but was released from jail in time to catch the next steamer going to Panama. He reached Panama at the end of five days, went to work for the Commission, and worked one day, but being taken sick, he quit work, though he did not report to the doctor. Instead, he again commenced drinking. On the second day of his disease, he was arrested by the Panaman police, and placed in jail as being drunk and disorderly. He was released on the third day of his disease and continued his debauch. He was again arrested on the fourth day, put in jail, and was then discovered by one of our inspectors who recognized that he was sick as well as drunk. He had him brought to Ancon Hospital, where he died on the sixth day from the beginning of his attack. The symptoms of the disease were well-marked, black vomit being profuse. An autopsy confirmed the diagnosis. Here was a man suffering from a case of yellow fever, of which he finally died on the sixth day, who, for the first five days of the disease, was about town, going from saloon to saloon, drinking immoderately, eating what came to hand, and sleeping where convenient. Twenty-four hours before he died, he rode up to the hospital in a cab and walked into the ward. He was having black vomit before he left the jail. It is often extremely difficult to trace a case of yellow fever and discover the source of infection. In 1909 we were very much startled by what appeared to be a case of this disease, which had apparently been contracted in the city of Panama, and developed there. A young Englishman had boarded the Royal Mail steamship at Southampton, bound for Colon. While the ship had touched at several points en route, the Captain certified that no one had left the ship at Cartagena, the only infected port at which she had touched. He arrived in Panama January 6, and after being in Panama six days, he developed yellow fever, of which he died on January 24. The symptoms were well marked, and an autopsy confirmed the diagnosis. As far as we knew, there had not been a case of this disease in Panama for four years, and the stegomyia were so scarce that we did not believe that yellow fever could be transmitted. The poor fellow, just before he died, told Dr. William Deeks, his attending physician, that on the night during which they were anchored in the Bay of Cartagena, the first mate and himself had slipped off unobserved in one of the ship’s boats, spent the night in Cartagena, and had gotten back to the ship before daylight. This confession at once cleared up the case. He had evidently been bitten by a stegomyia mosquito while in Cartagena. Had it not been for his confession, the evidence would have been very strong that in some way the disease had been contracted in Panama.