means of checking this yellow scourge and above all to Drs. Walter Reed and Lazear, whose lives helped to pay the price for the knowledge which finally vanquished yellow fever. Their associates on the board, Drs. Carroll and Agramonte, as well as Dr. Finlay, of Havana, are no less deserving of praise. The work of the Army board completed the excellent pioneer work of Surgeon Henry E. Carter on the incubative period of yellow fever. It follows that yellow fever can only be successfully combated by destruction of the mosquitoes by means of which it spreads. Quarantine measures against the disease are therefore concerned with isolation of all cases and very careful exclusion of every possible contact with mosquitoes by screening and elimination of all breeding places.
Cholera presents an entirely different picture from the standpoint of quarantine. Here we have a disease proved to be caused by an intestinal infection with a definite and characteristic microbe, the so called "comma" vibrio of Koch. The infection is limited absolutely to the intestinal tract, consequently the entire danger of spread of the disease is limited to the alvine discharges. The bacteria are taken into the system chiefly through the ingestion of infected drinking water, the contamination having arisen from sewage infection or other polluting contact with infected intestinal discharges. Uncooked vegetables and fruits are a secondary source of danger for like reasons. Preventive measures must also be extended to exclude articles of diet such as fresh fruits, for instance, which may tend to excite a tropical diarrhea and so produce a point of lowered resistance where the cholera germs can take effect. Quarantine measures, therefore, aim to isolate all frank cases and suspects, and to detain all who have been exposed, in small groups under close observation for at least five days,' covering the incubation period of cholera. Water and food supply must be above suspicion of carrying the germs, and strict cleanliness of person and quarters must be strictly enforced. It is absolutely essential that intestinal discharges from frank cases and suspects alike be thoroughly disinfected. Before convalescent cases are released from detention the intestinal discharges must be proved free from cholera germs by microscopical examination and bacteriological culture.
Smallpox is more familiar than the diseases just described, as are also the circumstances embodied in its quarantine control. Vaccination or proof of immunity by having had the disease are required of all persons exposed, which, of course, means all on board an infected vessel.
Typhus fever, the old time "ship" or "famine" fever, is very rare now in the United States, probably because of improved ship hygiene and sanitation, conditions always inimical to the disease. The last epidemics in this country were in Philadelphia in 1883 and in New York in 1891-92. Very rarely is a case seen at quarantine, but it is controlled by isolation, and disinfection of articles and quarters exposed to infection. Drs. Anderson and Goldberger, of the Hygienic Laboratory,
