The glands in the meantime become swollen and are surrounded by a sero-sanguinous exudation. The surrounding parts are œdematous. The glands usually do not suppurate, but they may do so and slough. The usual course after their enlargement is one of four: (1) resolution; (2) lengthened period of enlargement; (3) suppuration; (4) sloughing. In cases that recover the symptoms gradually take a favourable turn and recovery is as rapid as the attack. The fever slackens, the pulse becomes stronger, the tongue moist and the typhoid symptoms gradually pass away. The buboes either suppurate or subside; symptoms of secondary pyaemic conditions, however, may sometimes develop. Deviations from the typical course are, however, often observed. Some cases take an extremely rapid course, the patient succumbing within from 12 hours to two days. The duration of the disease varies between a few hours and a few weeks, but on an average up to the commencement of the convalescence it seems to last from 6 to 10 days. During convalescence the vitality of the issues are very low. Head symptoms sometimes persist for some time. Temper is irritable. The sloughing glands often take a long time to heal. Convalescence is soon established. _VARIETIES._ Just as before an epidemic of cholera visits a place, it is usual to observe cases of mild diarrhœa, and indigestion prevailing amongst its population; so, before plague actually breaks out, it has been found that cases of buboes and parotites with fever are commonly observed. Such cases were called _Pestis Minor_ at Astrakhan. “No one died from the disease _per se_, but few people were confined to bed.” It is not known whether in _pestis minor_ the plague germs could be found; but presumably not. Drs. Simpson and Cobb of Calcutta have described what is called _Pestis Ambulans_, or an ambulatory form of plague, in which plague germs have been found. The commonly accepted types of plague are (1) Fulminant; (2) Typical; (3) _Pestis Minor_ (including _ambulans_). The cause of the first two is the bacillus discovered by Kitasato, and they are very fatal, of the third, the cause may be an allied bacterium less potent to produce toxic effects on man, and it may come and go but plague may not break out. In ambulatory form the patient has slight fever and glandular enlargement, but he can move about. _DIAGNOSIS_—