STUDIES ON PNEUMONIC PLAGUE AND PLAGUE 

 IMMUNIZATION. 



IV. PORTAL OF ENTRY OF INFECTION AND METHOD OF 



DEVELOPMENT OF THE LESIONS IN PNEUMONIC 



AND PRIMARY SEPTIC^EMIC PLAGUE: 



EXPERIMENTAL PATHOLOGY. 



By Richard P. Strong and Oscar Teague. 

 {From the Biological Laboratory, Bureau of Science, Manila, P. I.) 



For the purpose of studying experimentally the question of 

 the portal of entry of the organism and the method of the 

 development of the lesions in pneumonic plague, animals were 

 placed in closed glass cages, and agar-cultures of virulent 

 pneumonic strains of the plague bacillus suspended in saline 

 solution were sprayed for a period of from about two to three 

 minutes into the surrounding air which they breathed. Thirty- 

 four normal guinea pigs and 55 normal monkeys were so infected 

 with plague bacilli, and all succumbed to plague infection. The 

 animals were necropsied in each instance, and the lesions present 

 observed and studied. It would be very tedious to record here 

 the individual necropsy reports, since the lesions found were so 

 often similar. Therefore, only a general description of the 

 lesions will be undertaken, and the different types of lesions 

 emphasized. 



In the guinea pigs so infected, the following changes were 

 encountered at necropsy. In general there was marked evidence 

 of plague infection about the cervical and laryngeal tissues. 

 The subcutaneous tissues showed extensive oedema, and there 

 was swelling of the cervical lymphatic glands and of those about 

 the trachea. Usually the glands were not only swollen but 

 more or less hsemorrhagic and presented the appearance of small 

 early buboes. Throughout the body marked evidences of sep- 

 ticaemia were usually present. There were frequently extensive 

 haemorrhages in the intestinal wall. The spleen sometimes 

 showed the typical changes encountered in bubonic-plague in- 



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