178 STRONG AND TEAGUE. 



reddened. There is no consolidation. The trachea is only slightly reddened. 

 The spleen slightly, if at all, enlarged. Smears from the heart's blood show 

 very numerous pest bacilli, while the organisms in the lung, liver, and 

 spleen are numerous. 



Monkey No. 5929. — Inoculated on December 5, died on December 10. 

 Necropsy: (By Dr. Crowell.) Smears from the spleen show very few, if 

 any, pest bacilli. The heart shows two or three to a field. Few are found 

 in the lung, while the liver shows numerous bacilli. The lesions are 

 practically the same as those encountered in monkey No. 5928. 



Therefore, these animals all died of plague septicaemia with 

 or without bubonic infection of the cervical glands; that is, 

 in the case in which the infection was severe and the sus- 

 ceptibility of the animals more marked, they succumbed to 

 septicaemia before cervical buboes developed. In none of these 

 instances was pneumonia present. Primary plague pneumonia 

 only results when infection by inhalation has in addition taken 

 place. 



It has been claimed by several observers and more recently 

 by Koulecha ^ that pneumonic plague in man is primarily a 

 septicsemic disease, the lungs becoming secondarily involved by 

 way of the blood circulation. According to this observer, the 

 infection is supposed to spread from the perivascular spaces to 

 the neighboring lung alveoli. He further believes that the bacilli 

 enter the blood by the lymph vessels through the lesions in the 

 tonsils and are deposited in the interstitial tissues around the 

 lung alveoli, the tonsils being regarded as the primary point of 

 infection. In some instances he assumes it to be possible for 

 the plague bacilli to pass from the mucous membranes of the 

 trachea and bronchi to the neighboring lymphatic glands and 

 from them to enter the blood and in this way later to reach 

 the lung. Albrecht and Ghon have shown that by the intra- 

 venous injection of plague bacilli in animals, pneumonic plague 

 did not result. 



In our opinion, the view that pneumonic plague is primarily 

 a septicsemic disease and that the lungs become secondarily in- 

 volved by way of the blood circulation and that the tonsil is first 

 infected is not acceptable. 



From our stu(j[y of pneumonic plague both in man ^ and 

 animals, we feel justified in concluding that infection in epidemic 

 pneumonic plague results from inhalation, the primary point of 



* Report of the International Plague Conference held at Mukden, April, 

 1911. Manila (1912), 154. 



^ For a description of the human lesions, see VII, p. 210 of this report. 



