PnoeuvLANts. As the eliminated bacilli may enter the healthy individual directly by euhine ous infection. by inhalation, or by ingestion (as has been abundantly proved), or may enter indi rectly, by means of flies, fleas, rats, etc., it is evident that inspection, isolation, and disinfec tion must be employed to prevent or limit an epidemic of plague. Among the preventive meth ods are general hygiene, good drainage, clean water-supply, cleanliness in dwelling houses, and cleanliness of streets. Isolation of the sick must be early employed. and infected dwellings must be thoroughly disinfected, as also wearing ap parel, lied linen, etc. Formaldehyde gas is probably the most thorough and convenient disinfectant. Chloride of lime is reconunended for disinfeeting farces, as well as for covering dead bodies of human beings, as well as of all animals dying during an epidemic. Isolation of the convalescent must be continued, according to Kitasato, for a month after apparent recovery; for the plague bacilli are found in the blood for a period varying from three to four weeks after the cessation of all symptoms of the disease. Itigid quarantine may be necessary during an epidemic.
Specific prophylaxis may be employed before or during an invasion of the dread disease by means of 'Yersin's antipest serum' or 'Haffkine's prophylactic fluid.' The serum devised by Yer sin is blood serum taken from horses that have been inoculated with the plague. Hypodermic
injection of the serum causes immediate hn munity, Ivhieh unfortunately lasts only 12 to 14 days. A difficulty in securing acquiescence in repeated injections at once arises. and as a popu lar treatment it is under a disadvantage. Haff kine's fluid is a culture of the Bacinits pestis rendered virulent by special methods, the bacilli, after abundant growth, being killed by an expos ure to a temperature of 70° C. for several hours. Inoculation with Haffkine's fluid has the ad vantage of conferring immunity lasting from a few days to several months. Calmette, director of the Pasteur Institute at Lille, France, states that a single inoculation of three cubic centi meters of HafTkind's fluid a month old estab lishes immunity only after the seventh day and for a variable period thereafter. A great disad vantage in the use of the prophylactic fluid lies in the facts that during immunization the person is more susceldible to plague; and that if he already had contracted even a mild attack, the inoculation would be fatal. Authorities recom mend the provision of antipest serum for prompt use in order to arrest an epidemic in the first eases, and the enutloyment of Haffkine's fluid to inoculate the people dwelling in localities threat ened with an invasion of the disease.