626 MICROBIOLOGY OF THE DISEASES OF MAN AND ANIMALS. 



respiratory tract. After involvement of the nearest lymphatic glands 

 the bacteria are distributed through the blood. 



Single attacks immunize. The antibodies developed are agglutinins, 

 are probably bacteriolytic, and possibly antitoxic bodies. The agglutin- 

 ation reaction is of value in diagnosis. 



The organisms are eliminated in the exudates from suppurating 

 buboes, from the sputum in the pneumonic type, and are present through- 

 out the body after death. The dead bodies of human beings and of 

 rats are sources of infection for other rats. There seems good evidence 

 of these animals becoming chronic carriers though showing no symptoms 

 of disease, and may thus be important factors in maintaining and spread- 

 ing plague. 



The disease is largely communicated by means of fleas which have 

 become infected by living on other human beings or even upon rats. 



Prophylaxis consists of isolation of pneumonic cases, thorough 

 disinfection involving the killing of fleas, and chiefly the destruction of 

 rats, squirrels, and other animals which may serve as carriers. Haffkine's 

 vaccination method has also been shown to be a valuable prophylactic 

 measure. 



The serum of immunized animals has been tried as a therapeutic 

 agent and gives encouraging results when administered in the early stages. 



SWINE ERYSIPELAS.* 

 Bacterium rhusiopathia suis. 



Swine erysipelas is an infectious disease of hogs characterized by red 

 or violet discoloration of the skin and mucous membranes. Swine 

 erysipelas does not exist in the United States but is very prevalent in 

 continental Europe. It is caused by a very small, slender, non-motile, 

 non-spore-bearing bacterium (Bact. rhusiopathia suis) which stains by 

 Gram's method, and grows feebly on the ordinary culture media. Devel- 

 opment is best under anaerobic conditions. In gelatin stab cultures, 

 after three or four days, a white growth can be seen along the needle 

 puncture. Radiating from this are a number of delicate tufts which give 

 the growth the appearance of a fine test-tube brush. White and gray 

 mice, white rats, and pigeons succumb to the inoculation of minute 

 amounts of the culture. The bacteria tend to collect within the bodies 



* Prepared by M. Dorset. 



