Although the characteristics of pulmonary involvement, with expectoration of blood, were noted by many observers of the 14th century and later as manifestations of plague, yet in the present pandemic, which started in 1894, such cases were at first overlooked as being plague. The recognition of a primary pneumonic plague was made by Childe in 1897. The onset is sudden, with a rise of temperature to 103°F., or higher, during the first day. The marked physical exhaustion and clouding of the consciousness, characteristic of any type of pestis major, are intensified in pneumonic plague. In fact the occurrence of manifestations of such profound toxaemia in the presence of only slight physical signs, should make one suspicious. Crepitation over small areas, without demonstrable dulness on percussion, may be the only sign. There is often early dyspnoea and rapid shallow respiration. Cough, with the expectoration of rather abundant watery sputum, which soon becomes blood-stained or absolutely sanguineous, may be present by the second day. [Illustration: FIG. 68.—Axillary Bubo. (Reproduced from Simpson’s Treatise on Plague, 1905.) From Jackson’s Tropical Medicine.] There is never the rusty, tenacious sputum of lobar pneumonia. Herpes never appears, according to Childe. Heart failure is a very prominent feature of plague pneumonia. It is fortunate that this watery sputum teems with bacilli early in the disease as smears from such sputum give an early and sure diagnosis of this terribly contagious and fatal malady. The knowledge that this infection is transmitted from man to man by the droplets of sputum expelled in coughing demands the protection by some form of mask of anyone coming near such a patient. Some observers noted splenic enlargement and tenderness over the superficial lymphatic glands. Strong has noted that the course of the disease rarely extends beyond the fourth day and that death is the invariable termination. In 1919 thirteen cases of plague pneumonia occurred in California starting from an at first unrecognized case of bubonic plague of squirrel origin. These pneumonias were diagnosed as influenza pneumonias but later the true diagnosis was determined. McCoy notes in this connection that there is a strong tendency to pulmonary localization of plague in the squirrel which is not true of the rat. =Septicaemic Plague.=—As regards the clinical manifestations of septicaemic plague, if such be considered as a separate type, Choksy states that there is no clinical sign by which such a septicaemia can be recognized without the help of the laboratory, although the presence of a thready or imperceptible pulse, in one showing the characteristic toxaemia of plague, should cause suspicion.