BACILLI OF THE COLON. 57 



The typhoid bacillus is both a saprophyte and a 

 parasite. As a saprophyte it is widely distributed in 

 nature, due to its ability to adapt itself to its environ- 

 ment. It will live in water, ice, sewage, milk, dust, 

 air, and soil. In surface-water typhoid bacilli will 

 live about a week, being rapidly overgrown by other 

 bacteria, but in distilled water they will live for three 

 months. Freezing will kill most of them in a few 

 days. Experiments made by placing typhoid bacilli 



Fig. 6. Typhoid bacilli showing flagella. X 1100 

 times. (After Loffler.) 



in ice prove that nearly all are killed in a week, but 

 occasionally they live for three months. The bacillus 

 will retain life for six months in the upper layers of 

 the soil. 



Within the body they can resist the action of the 

 gastric juice and multiply in the small intestine, where 

 the greatest amount of damage is done. During the 

 disease the typhoid bacilli may be found in the cir- 

 culating blood, spleen, mesenteric lymphatic glands, 

 rose-spots, and occasionally in the sputum and 

 vomitus. Typhoid fever therefore should be con- 

 sidered not as a local infection of the intestine, but as 

 a general infection with the organisms present in many 



