BACILLUS TYPHOSUS 109 



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 proved by the fact that when known 

 infected sewage is no longer dumped into a water supply 

 typhoid fever ceases to be prevalent among the users of the 

 water. Ice is said to be another method of transmitting this 

 disease. It is best not to inculpate the ice itself, since freezing 

 kills whatever germs are not squeezed out in the contraction 

 of the water when becoming solid, but rather blame the dirty 

 methods of cutting, storing, and distributing. Ice not 

 infrequently becomes covered with manure and earth in 

 storing and lading for distribution. The unwashed hands 

 of the ice-man are only too familiar. When ice is placed in 

 the water cooler in public places it is frequently washed under 

 a spigot and then picked up in the hands of the distributor. 

 Typhoid bacilli do not multiply to any considerable extent 

 in water, but merely remain viable. 



Milk is a profile source of spread, since it is easy for the 

 dairyman with a case of typhoid on his farm to infect this 

 product. Fresh milk has a mild restraining effect upon 



