A Note on the Epidemiology of Pneumonic Plague

Primary pneumonic plague is a well recognised form of the disease, but on account of its comparative rarity it has not attracted much attention and very little has been done to establish its bionomics and in particular its relationship to the more common bubonic variety of the disease. This is the more surprising since it presents certain well marked characteristics both clinical and epidemiological which serve to distinguish it from all other manifestations of the disease. But af art from the purel}' scientific aspect of the question a proper appreciation of the part played by pneumonic plague in the natural his tor}7 of plague, as a whole, is of some practical importance. It is not too much to say that at present the position occupied by pneumonic plague is that of a curious variety of the disease, which on account of its rarity is of but little practical importance. Thus, Major Lamb, I.M.S., in his summary of the work of the Plague Commission dismisses the subject briefly in the following words :? " Pneumonic plague is highly contagious. It is, however, rare (less than 3 per cent, of all cases) and plays a very small part in the general spread of the disease. "