ment of the lymphatic glands apparent during life, although after death the glands throughout the body are found to be somewhat enlarged and congested. The high degree of virulence and rapid course of the disease depend on the entry of large numbers of the bacilli into the blood, where they can be readily found during life. The patient is prostrated from the outset ; he is pale and apathetic; there is no, or very little, febrile reaction (100° F.). Great weakness, delirium, picking of the bedclothes, stupor, and coma end in death on the first, second, or third day. Frequently in these cases there are hæmorrhages.
Pneumonic plague.— This type of the disease, which was carefully studied by Childe and others, is especially dangerous as well as deadly: dangerous because of the multitude of bacilli which are scattered about in the patient's expectoration,*[1] and because the clinical symptoms are unlike those of typical plague, and are apt to be mistaken for some ordinary form of lung disease. The illness commences with rigor, malaise, intense headache, vomiting, general pains, fever, and intense prostration. Cough and dyspnœa set in, accompanied by a profuse watery blood-tinged sputum. The sputum is not viscid and rusty, as in
- ↑ * smaller|During the epidemic of pneumonic plague in Manchuria from October, 1910, to March, 1911, R. P. Strong and Teague exposed 82 agar plates at distances varying from 5 cm. to 2 metres in front of the faces of plague patients for a period of two minutes. In 39 instances the patient did not cough, and only 1 of the plates yielded plague bacilli. In 35 instances the patient coughed; the corresponding plates yielded plague cultures in 15 instances, the growths having originated in the invisible spray.}} The vitality of the plague bacillus outside the body depends in great measure on the rate of evaporation, that is to say, on the temperature and hygrometric conditions of the air. Thus in Harbin the bacillus retained its vitality for long periods when the thermometer stood at— 9° C. and the water deficit equalled about 0.3 mm. of mercury. In India, where evaporation goes on much more rapidly at temperatures perhaps of 30° C. and water deficit of 9.5 mm. of mercury, pneumonic plague is much rarer, amounting to only 3 per cent, of the total cases. In Manchuria there were only two or three cases of bubonic plague in a total of some 50,000 deaths. The initial case of this epidemic is said to have been that of a tarbagan hunter, who contracted his infection in skinning one of these animals. Domestic animals, donkeys and dogs were attacked during the epidemic and contributed to its spread.
