TYPHOID FEVER. 173 



How is it fatal to animals? 

 What animals are susceptible? 

 How is It differentiated from other bacilli? 

 What is the effect of a non-fatal attack of this disease? 

 How does symptomatic anthrax compare with malignant oedema ? 

 What is anaphylaxis? 



How is active immunization practised on animals with extract of infected 

 meats ? 



What is Bacillus aerogenes capsulatus ? The Bacillus botulinus ? 



CHAPTER XVII. 

 TYPHOID FEVER. 



Bacillus Typhosus. 



History. The presence of a microorganism in cases of 

 typhoid fever was discovered by Eberth, in 1880; it was 

 named the Bacillus typhosus ; but until isolated and described 

 by Gaffky, in 1884, it was not fully recognized. 



It is found after death in the blood, spleen, liver, intestines, 

 Peyer's patches, and mesenteric ganglia, and during life in the 

 blood, especially when the same is taken from the spleen by 

 means of a hypodermatic syringe, in the rose patches, in the 

 urine and feces, and outside the human body, occasionally in 

 water and soil contaminated with dejecta of typhoid patients, 

 and often in milk, which is due probably to the cleansing of 

 the utensils in which the milk is collected with water con- 

 taminated with the bacilli (Figs. 63 and 64). 



Morphology. The Bacillus typhosus appears as a rod with 

 rounded extremities, from 2 to 4 mikrons in length, and 0.6 to 

 0.8 mikron in breadth. At times it appears as short ovals ; at 

 others the bacilli are joined together, forming long threads. 

 It stains with all the anilin dyes, but not quite so readily as 

 other bacteria. It does not stain by Gram's method. In 

 stained preparations clear spaces are observed in the body of 

 the cells. This has given rise to the belief that the bacteria 

 contain spores. There are, however, no spores, for those clear 



