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XX] ordinary pneumonia. Moist râles are audible at the bases of the lungs, the breathing becomes hurried, other symptoms rapidly become worse, delirium sets in, and the patient dies on the fourth or fifth day. This is the most fatal as well as the most infectious form of plague.

Abortive or larval plague (pestis minor, pestis anibulans).— Certain epidemics are distinguished by the large proportion of mild cases. In such, buboes form and suppurate or resolve, the associated constitutional symptoms being comparatively mild, or perhaps altogether wanting. In every epidemic there may be cases in which the patient is able to be about, having little if any fever, and apparently being little inconvenienced by the disease. Such cases, however, may collapse suddenly.

Epidemics of bubo with little or no constitutional symptoms, which precede and follow true plague, sometimes occur. The cases forming this group are of great importance in their bearing on the spread and prevention of the graver form of the disease.

Relapses, though rare, do occur, and are dangerous.

Mortality.— The case- mortality of bubonic plague varies in different epidemics. It is usually greatest at the beginning and height of the epidemic. Disregarding those mild epidemics just alluded to, the death-rate may be anything from 60 to 95 per cent, of those attacked. Much appears to depend on the social condition of the patient and the attention and nursing available. Thus in a recent Hong Kong epidemic, whilst the case-mortality among the indifferently fed, overcrowded, unwashed, and almost unnursed Chinese amounted to 93.4 per cent., it was only 77 per cent, among the Indians, 60 per cent, among the Japanese, and 18.2 per cent, among the Europeans, a gradation in general correspondence with the social and hygienic conditions of these different nationalities. In the South American epidemics and in the recent circumscribed epidemics in Europe the mortality was only about one-third of that obtaining in India and