Pathogenesis 



637 



There is always well-marked blood-infection during the first 

 weeks of the disease, and upon this depend^ the occurrence of the 

 rose-colored spots. 



The bacilli enter the solitary glands and Peyer's patches, and 

 multiply slowly during the incubation period of the disease — one to 

 three weeks. The immediate result of their activity in the lymphatic 

 structures is an increase in the number of cells, the ultimate effect 

 is necrosis and sloughing of the Peyer's patches and solitary glands. 

 From the intestinal lymphatics the baciUi pass, in all probability, 

 to the mesenteric nodes, which become enlarged, softened, and 

 sometimes rupture. They also invade the spleen, liver and some- 



_ Fig. 257.^ — Intestinal perforation in typhoid fever. Observe the threads of 

 tissue obstructing the opening. (Museum of the Pennsylvania Hospital.) 

 (Keen, "Surgical Complications and Sequels of Typhoid Fever"). 



times the kidneys, and other organs where they may be found 

 in small clusters in properly stained specimens. 



Mallory* found the histologic lesions of tj^hoid fever to be wide- 

 spread throughout the body and not limited to the Peyer's patches of 

 the intestine, where they are most evident. His conclusions regard- 

 ing the pathology of the disease are briefly: "The typhoid bacillus 

 produces a mild diffusible toxin, partly within the intestinal tract, 

 partly within the blood and organs of the body. This toxin pro- 

 duces proliferation of the endothelial cells, which acquire for a 

 certain length of time malignant properties. The new-formed cells 

 are epithelioid in character, have irregular, lightly staining, ec- 

 * "Journal of Experimental Medicine," 1898, vol. iii, p. 611. 



