332 PATHOGENIC BACTERIA. 



ease becomes worse they assume a sitting posture with 

 the back much bent ; the eyelids are glued together by 

 adhesive pus ; and when death comes to their relief, in 

 the course of forty to sixty hours after inoculation, they 

 remain sitting in the same characteristic position. 



When the ears of rabbits are inoculated with the 

 bacillus from cases of erysipelas suis, a violent inflam- 

 matory edema and distinct redness occurs, much re- 

 sembling erysipelas. This lesion gradually spreads, in- 

 volves the head, then the body of the animal, and ulti- 

 mately causes death. 



When swine are affected, they are dull and weak, and 

 have a kind of paralytic weakness of the hind quarters. 

 The temperature is elevated ; red patches appear upon 

 the skin and swell and become tender. Death follows in 

 two or three days. 



In all animals the anatomical changes are much alike. 

 The disease proves to be a septicemia, and the bacilli can 

 be found in all the organs, especially the lungs and spleen. 

 They are few in number in the streaming blood. 



As the organisms stain well by Gram's method, this 

 stain is of great value for their discovery in the tissues, 

 and can be highly recommended. 



Most of the bacilli occupy the capillary blood-vessels ; 

 many of them are enclosed in leucocytes. The organs in 

 such cases do not appear distinctly abnormal, except the 

 spleen, which is considerably enlarged. The mesenteric 

 and other lymphatics are also enlarged, and the gastric 

 and intestinal mucous membranes are usually inflamed 

 and mottled. The bacilli also occupy the intestinal con- 

 tents, and Kitt, who discovered them in this position, 

 points out that the infection of swine probably takes 

 place by the entrance, along with the food, of the fecal 

 matter of diseased animals into the alimentary apparatus 

 of others. 



Pasteur, Chamberland, Roux, and others have worked 

 upon a protective vaccination based upon the attenuation 

 of the virulence of the organism by passing it through 



