488 INFECTION AND IMMUNITY. 



tion of the organisms. Compared with pneumonic 

 and septicemic plague the bubonic form is much 

 less dangerous to a community. 



Following cutaneous infection the regional 

 lymph glands become swollen and hemorrhagic, 

 and undergo more or less extensive necrosis. When 

 the infection extends beyond the lymph glands the 

 blood may contain enormous quantities of bacilli 

 (plague septicemia), and the same condition fol- 

 lows plague pneumonia ; in the event of general in- 

 fection death follows in a few hours. "Secondary 

 pneumonia" and also "secondary buboes" develop 

 as a consequence of blood infection. Hemorrhages 

 into the mucous membrane (especially the stom- 

 ach or cecum), endothelial surfaces (pericardium), 

 and various parenchymatous organs, with extreme 

 degeneration of the latter (liver, kidneys and 

 heart), are characteristic anatomic changes. The 

 spleen is usually swollen. The toxic substance 

 evidently has affinities for many tissues. 



Mixed infection with the streptococcus is not 

 uncommon and is a serious complication. 



prophylaxis. The following are important points for prophy- 

 laxis: 1. Early diagnosis as established by bac- 

 teriologic examination of blood, sputum, and fluid 

 taken from a bubo either by a syringe or after in- 

 cision ;' 2, in the thorough isolation of patients and 

 of those who have been exposed to infection; 3, 

 in the disinfection of excretions, of clothing and of 

 infected houses, which in some instances may 

 mean the destruction of the latter; 4, in the de- 

 struction of rats; 5, prophylactic injections. Up 

 to the present time the most effective measure of 

 getting rid of rats is to offer a bounty for each 

 animal caught, as practiced in Manila. In Cali- 



