THE INFECTIOUS DISEASES. 



233 



from the vessels of the spleen and intestine. Necrotic changes may 

 develop in and about these focal cell accumulations. 



Simple focal necroses of the livy and of other viscera, due to the 

 action of toxic substances in the body fluids, may occur in typhoid fever 

 as in many other iiifeclius diseases. ^ 



FIG. 114. HYPEIIPLASIA OK ENDOTHF.LIUM ;N THE LIVER IN TYPHOID FEVER. 

 This cut shows a more highly magnified portion of the focal lesion in Fig. 108. 



While small foci of cell proliferation may be present .in the 

 as well as other viscera, their occurrence is neither so frequent nor so~ 

 characteristic as in the liver. 



In typhoid fever as in other infections diseases toxaemia may be mani^ 

 fested by disturbance iu^ the circulatory, respiratory, and heat-retrulatiiig 

 mechanism, and in general metabolism as well as by manifest lesion_s. 

 siich as albuminous or other degeneration of parenchyma cells through- 

 out the body, and alteration leading to leucocy tosis. 



SECONDARY LESJOJ^. 



In addition to the more characteristic lesions of typhoid fever which 

 we have described, there are several of secondary or complicating nature. 

 These are of sufficiently frequent occurrence in the disease to require 

 brief mention. They are in part due to the direct action of the typhoid 

 hppil1i|f| flr its soluble poisons : in part^ however, are brought about by* 

 secondary bacterial infections";* but between these it is often, with our 

 present knowledge^ impossible to distinguish." 



The Digestive Organs. In the intestine there may be gangrene, some- 

 times involviugthe tissues abpj^t the ulcers^ sometimes apart from 



1 For fuller details of studies on these focal lesions in typhoid and other infectious 

 diseases, consult Mallory, loc. cit. Reed, Johns Hopkins Hospital Reports, vol. v., 1893. 

 Flexner, ibid., vol. vi., p. 259, 1897. 



' 2 For bibliography of the extra-intestinal lesions induced by the typhoid bacillus 

 see Howard, Philadelphia Monthly Med. Jour., vol. i., IMo. 7, p. 402, 1899. 



