Pathogenesis 635 



Opposed to this view is the rarity with which the baciUi are found in 

 the water, in favor of it the almost invariable decline in the incidence 

 of the disease when the water supply is purified or filtered, and the 

 continued low incidence thereafter. 



Next to water, milk is probably the most frequent vehicle through 

 which it is admitted to the body. Schiider* found that no, out of 

 460 epidemics that he studied, could be referred to milk. 



Rosenau, Lumsden, and Kastlef were able to connect 10 per cent, 

 of the cases of typhoid fever occurring in the District of Columbia 

 with infection through milk. Interesting additional facts upon the 

 subject can be found in Bulletin No. 41 of the Hygienic Laboratory 

 upon "Milk in its Relation to the Pubhc Health." The bacillus 

 may occasionally enter milk in water used to dilute it or to wash the 

 cans, but may also be directly introduced by the hands of careless 

 milkers who are carriers, or be conveyed from infected fecal matter 

 by flies. 



The occurrence of typhoid fever among the soldiers of the United 

 States Army during the Spanish-American War in 1898 was shown by 

 Reed, Vaughan, and ShakespeareJ to be largely the result of the 

 pollution of the food of the soldiers by flies that shortly before had 

 visited infected latrines. 



The bacillus is also occasionally present upon green vegetables 

 grown in soil fertilized with infected human excrement or sprinkled 

 with polluted water. Conn§ investigated an epidemic of typhoid 

 fever at Wesleyan College, and believed that he traced it to the 

 eating of raw oysters that had been "fattened" in sewage-polluted 

 water. Broadbentj| believed an outbreak of the disease in England 

 to be traceable to the same cause. Newsholme** found that in 56 

 cases of typhoid fever about one-third were attributable to eating 

 raw shell-fish from sewage-polluted beds. Footeft found that when 

 typhoid bacilli were placed in water containing oysters, they could 

 be found alive in the mollusks for three weeks after they had dis- 

 , appeared from the water. 



Pathogenesis. — ^The primary activities of the typhoid' bacillus 

 are unknown. It is supposed that it passes uninjured through the 

 acid secretions of the st.omach to enter the intesine, where local dis- 

 turbances are set up. Whether during an early residence in the 

 intestine its metabolism is accompanied by the formation of a toxic 

 product, irritating to the mucosa, and affording the bacilli means of 

 entrance to the lymph-vessels, through diminutive breaches of con- 

 tinuity, is not known. We usually find it well established in the 



* Zeitschrift fiir Hygiene, 1901, xxxviii, 343. 



t "Hygienic Laboratory Bulletin No. 33," Washington, D. C, 1907. 



t "Report on Typhoid Fever in the U. S. Military Camps in the Spanish War," 

 vol. I. 



§ Medical Record, Dec. 15, 1894. 



11 Brit. Med. Jour., Jan. 12, 1895. 

 **Brit. Med. Jour., Jan., 1895. 

 ' tt Med. News,' 1895. 



