INFECTION ATRIUM. 437 



The bacilli gain access to the body through The 

 the lymphoid tissue of the intestinal tract (Pey- 

 er's patches and the solitary follicles). The occur- 

 rence of primary infection of the lungs through 

 inhalation of infected dust is possible, but has 

 not been definitely proved. In this instance typhoid 

 baci Hernia might occur either with or without 

 intestinal infection. In the latter case it would 

 seem essential that some local lesion exist in 

 the lungs or elsewhere from which organisms 

 could constantly be supplied to the blood Neufeld 

 doubts the ability of the typhoid bacillus to pro- 

 liferate in the blood, because of the strong bacteri- 

 cidal power of the latter, and considers that infec- 

 tion takes place through the intestines even in cases 

 of "typhoid without intestinal lesions." 



The incubation period is subject to considerable incubation 

 variations. In a series of cases in which the date 

 of exposure was known, 62 per cent, showed symp- 

 toms in from 20 to 25 days, 2 per cent, in from 14 

 to 20 days, and 2 per cent, later than 30 days. 



Quickly following the development of intestinal Localization 

 lesions, the bacilli reach the circulation by way Bacilli. 

 of the lymphatics, and through the action of the 

 bactericidal constituents of the blood (amboceptor- 

 complement complex and possibly leucocytes) they 

 are killed and dissolved in large quantities. It 

 is now generally believed that only through the 

 disintegration of the bacterial cells are their toxic 

 constituents thrown into solution in the body, a 

 condition which is necessary in order that the tis- 

 sues be injured. Infection of the blood stream 

 with living organisms, in the early stages of the 

 disease and preceding relapses, occurs in probably 

 all the cases. 



