If repetitions of any of the foregoing principles occur it is hoped that, when taken in connection with concrete applications cited, they will not appear as redundant. THE MANILA EPIDEMIC OF 1912 TO 1914.--The chronologic facts concerning the development and extension of plague in Manila in 1912, 1913 and 1914 are as follows: The disease made its reappearance in Manila, after an absence of six years for the human disease and five years for rodent plague, two verified human cases having been recorded in June, 1912. Preceding the appearance of the first Manila cases there occurred upon incoming ships a number of cases of plague during the Spring of 1912, detected at quarantine. Although there is no conclusive evidence which connects these imported cases, originating in Hong Kong, China, with the epidemic which broke out in Manila a few months later, the fact of their occurrence and recognition is interesting enough for us to consider before taking up the study of the Manila epidemic. Concerning these imported cases Dr. Victor G. Heiser, then Director of Health for the Philippines, wrote as follows in the _Philippine Journal of Science_, in February, 1914. UNUSUAL CHARACTER OF PLAGUE AT QUARANTINE.--It is perhaps worthy of note that, prior to the appearance of plague in Manila a number of cases of the disease were found on incoming steamers. For instance, on April 6, 1912, a death was reported on the steamship _Zafiro_, which had arrived the day previous from Hongkong and had been in the harbor for twenty-four hours at the time of the death. At the medical inspection of the vessel, which was made the day previous, no illness was detected. An investigation showed that the victim had been on deck on the night of April 5, 1912, in apparently good health. The next morning, at 6 o'clock, he was found dead in his bunk. The necropsy and subsequent biological findings reported by Dr. R. P. Strong of the Bureau of Science showed that death was due to pneumonic plague. On April 7, 1912, the steamer _Loongsang_ arrived in Manila from Hongkong, and the captain reported that a death had occurred the day previous in a Chinese member of the crew. Upon investigation of this case, the captain stated that the man was apparently in good health, but that while hauling on a rope he fell over in an apparent faint and was placed in a chair and in the course of a few hours expired. The necropsy and animal inoculations showed that he had died of plague and probably of the pneumonic variety. Beginning April 7, 1912, the temperature of all members of the crew and of the passengers that arrived in vessels from foreign ports was taken with a view to detecting any possible cases of plague.