THE TYPHOID BACILLUS 



107 



or years after recovery from typhoid fever. These agglutinins are specific 

 for the typhoid bacillus and their detection forms an important diagnostic test. 



FIG. 21. TYPHOID BACILLUS. 



Upper half of field showing clumps. Lower half of field showing bacilli free from clumps 



after filtered through paper. 



FIG. 22. TYPHOID BACILLUS. 



A. Agar culture, showing a few short filaments. B. Broth culture. Filaments much 

 longer and more numerous. (12 X eyepiece and Ma oil immersion objective.) 



Specific precipitins, agglutinins and lysins occur in the serum of animals im- 

 munized against the typhoid bacillus by inoculation with sterilized bacilli. 



Pathogenesis. The typhoid bacillus is the specific cause of typhoid fever, a 

 septicemia with localized lesions in the small intestine. 



