BACILLUS TYPIIOSUS 119 



the softened part separates and is removed, a ragged, 

 punched-out ulceration remains. This ulceration may 

 be progressive and eat into bloodvessels, causing 

 intestinal hemorrhage so common in this disease. If 

 the ulceration be directed out toward the peritoneal 

 surface of the intestine, perforation and peritonitis 

 may ensue. The presence of the typhoid bacilli and 

 their toxins in the organs, notably the spleen, causes 

 characteristic changes which need not be dwelt upon 

 here. 



Typhoid fever is more common in men between the 

 ages of twenty and thirty-five years. Spring and 

 autumn are the seasons of greatest prevalence. It 

 spreads from patient to patient usually through the 

 intervention of food and drink and accidental or chronic 

 carriers. Water and food polluted by flies that have 

 soiled their bodies upon excreta, form the greatest 

 sources of indirect propagation. Water is polluted 

 by the dumping of sewage containing typhoid germs 

 into a water course used as a drinking supply. Typhoid 

 bacilli can live within a particle of feces over the 

 winter, so that the infection of a water course in the 

 spring is not to be wondered at. When winter breaks 

 up the spring rains wash down the hillsides, sweeping 

 before them surface collections into streams. The 

 greatest danger, however, exists when towns empty 

 their sewerage systems into a stream from which 

 other communities lower down take their domestic 

 supply. This means of spread is proven by the fact 

 that when known infected sewage is no longer dumped 

 into a w r ater supply typhoid fever ceases to be prevalent 

 among the users of the water. Ice is said to be another 



