i378 Me EISffEROlDEA GROUP OF TROPICAL PBVBRS 



second week. These ulcers may increase in depth by an extension 

 of the necrosis, and may lead to perforation; on the other hand, 

 there may be a formation of granulation tissue over the base, which 

 subsequently leads to fibrous tissue formation, and thus eventually 

 to the healing of the ulcer, which process is completed by the growth 

 of the mucosa over the young fibrous tissue. The site of a previous 

 typhoid ulcer is often clearly visible as a depressed pigmented area, 

 which, on microscopical examination, is seen to consist of atrophic 

 mucosa covering a fibrous submucosa, which is also often atrophic. 



The mesenteric glands show at first hypersemia and cell prolifera- 

 tion, among which the typical bacilli can be found. Pus formation 

 may also be found at times. 



The spleen early becomes hypersemic, and swells considerably, 

 remaining enlarged until the third or fourth week. The capsule 

 becomes tense, and the pulp assumes a dark red colour. The 

 swelling is due to the hypersemia and cellular infiltration with leuco- 

 cytes, endothelial cells, and macrophages, among which the typhoid 

 bacilli may be found. During the third week the pulp becomes 

 softer, and the Malpighian bodies become prominent, and absorption 

 begins to take place, which produces a paler colour in the pulp, and 

 eventually leads to an increase in the amount of fibrous tissue. 



The liver shows cloudy swelling and fatty degeneration of the 

 cells and spots of focal necrosis, which may be produced by accumu- 

 lations of epithelioid cells in the lymphatic spaces of the portal 

 system, or to small areas of necrosis of liver cells owing to occlusion 

 of adjacent capillaries. These foci are associated with clumps of 

 the specific bacilli. 



The kidneys show cloudy swelling of the cells of the convoluted 

 tubules, but in the cases when the kidney is specially involved there 

 may be considerable hypergemia, together with perivascular cellular 

 exudation and granular degeneration of the cells of the convoluted 

 tubules. 



The heart muscle may show fatty or, rarely, waxy degeneration, 

 while endarteritis obliterans in the small arteries is said to be seen 

 in cases of sudden death without obvious cause. 



In the nervous system there are no very marked changes, but 

 pigmentation of the ganglion cells and leucocytic infiltration of the 

 perivascular spaces may be seen, as well as fatty degeneration of 

 the nerve fibres. 



The bone-marrow is generally congested, and may show signs of 

 focal necrosis, with hyperplasia of lymphoid cells and clumps of 

 typhoid bacilli. 



Symptomatology .—Enteric fever is a very protean disease, the 

 description of which is usually divided into incubation period, 

 onset, course, subdivided into weeks, relapses, and terminations in 

 death or convalescence. In general terms, it may be stated that 

 the fever presents physical signs and symptoms not unlike those 

 Seen in the Temperate Zone, but a number of cases are atypical. 



These atypical cases may have a slight and short attack of fever 



