PATHOLOGICAL CHANGES. 333 



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 

 congestion. 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. 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. Clumps 

 of bacilli may also occur in the kidney. 



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

 widespread cellular degenerations in the form of cloudy swelling of the 

 specialised cells of the liver and kidney, or of the muscular fibres of 

 the heart. A granular disintegration of such cells may occur. As 

 they may exist altogether apart from local presence of the bacilli, these 

 changes suggest the circulation in the blood of soluble poisons. 



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

 of acute broncho-pneumonia. In these, typhoid bacilli may some- 

 times be observed, but evidence of a toxic action depressing the 

 powers of resistance of the lung tissue is found in the fact that the 

 pneumococcus is frequently found in such complications of typhoid 

 fever. 



The nelsons 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. 



The typhoid bacilli probably travel by the blood stream, but they 

 have not been frequently isolated from the blood. Whether they have 

 ever been found in the roseolar spots which occur in typhoid fever is a 

 subject of dispute. The fact that the typhoid bacilli are usually con- 

 fined to certain organs and tissues, shows that they must 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 re- 

 action is set up, and which in the intestine is sufficiently 



