PATHOLOGICAL CHANGES 363 



no relation to its severity. Small ulcers may occur in the 

 Ivmphoid follicles of the large intestine. 



The me&enteric glands corresponding to the affected part of 

 the intestine are usually enlarged, sometimes to a very great 

 extent, the whole mesentery being filled with glandular masses. 

 In such glands there may be acute inflammation, and occasion- 

 ally necrosis in patches occurs. Sometimes on section the 

 glands are of a pale-yellowish colour, the contents being diffluent 

 and consisting largely of leucocytes. Typhoid bacilli may be 

 isolated both from the glands and the lymphatics connected with 

 them, but the b. coli is in addition often present. 



The spleen is enlarged, on section usually of a fairly firm 

 consistence, of a reddish-pink colour, and in a state of conges- 

 tion. Of all the solid organs it usually contains the bacilli in 

 greatest numbers. They can be seen in sections, occurring in 

 clumps between the cells, there being no evidence of local 

 reaction round them (Fig. 106). Similar clumps may occur in 

 the liver in any situation, and without any local reaction. In 

 this organ, however, there are often small foci of leucocytic 

 infiltration, in which, so far as our experience goes, bacilli 

 cannot be demonstrated. The bacillus is found, often in large 

 numbers, in the gall-bladder, where it may persist for years 

 (vide infra). Clumps of bacilli may also occur in the kidney. 



In addition to these local changes in the solid organs, there are also 

 \\ i(lc>j)ic;i(l cellular degenerations in the solid organs which suggest the 

 action of toxic products. 



In the lunys there may be bronchitis, patches of congestion and of 

 acute broncho-pneumonia. In these, typhoid bacilli may sometimes be 

 observed, but evidence of a toxic action depressing the powers of resist- 

 ance of the lung tissue is found in the fact that the pneumococcus 

 frequently occurs in such complications of typhoid fever. 



The nervous system shows little change, though meningitis associated 

 either with the typhoid bacillus, with the b. coli, or with the strepto- 

 coccus pyogenes has been observed. 



In typhoid fever the bacilli can in 90 per cent, of cases be isolated from 

 the blood during the course of the illness. The local lesions are thus associ- 

 ated with a general septica. j mic process. The bacilli have been found in 

 the rofteolar spots which occur in typhoid fever, but it cannot he yet 

 stated that such spots are always due to the presence of the bacilli. The 

 fact that the typhoid bacilli are usually confined to certain organs and 

 tissues shows that they probably have a selective action on certain tissues. 



To sum up the pathology of typhoid fever, we have in it a 

 disease the centre of which lies in the lymphoid tissue in and 

 connected with the intestine. In this situation we must have 

 an irritant, against which the inflammatory reaction is set up, 



