■">N6 ACUTE GENERAL INFECTIOUS DISEASES 



Pathology.— The most pronounced pathological changes 

 are found in the intestines, heart and lungs. In the acute 

 form the following lesions are found: 



(a) The intestines show marked pathological changes. 

 The mucous membrane throughout the entire tract is 

 highly congested and covered in numerous places with 

 darker areas. The intestines contain a thin, watery, 

 frothy, mucopurulent and yellow exudate often mixed with 

 blood and bile giving them a dark greenish tinge. Defects 

 in the mucosa are often present, the apex of the intestinal 

 villi are often eroded, and in some cases croupous exudate 

 is present, in others ulceration. All of these changes in 

 the mucosa may be observed in the same case. The mucous 

 membranes of the pharynx, crop, colon and rectum show the 

 most pronounced lesions. The mesenteric lymph glands 

 are nearly always enlarged, edematous and show numerous 

 petechia? . 



(b) The heart shows, as a rule, distinctive changes. It 

 is covered with small, dark red, pin-point dots, and the 

 bloodvessels congested. The epicardium is often covered 

 by a fine fibrinous membrane. The pericardial fluid is 

 nearly always cloudy, containing some fibrinous flakes. 

 In the peracute form of the, disease these changes are not 

 so prominent. 



(c) The lungs are .found congested, thickened, dark red 

 in color, very heavy (hepatized); the milder type will show 

 congestion and edema. In the subacute form fibrinous 

 pleuritis is frequently noted. The larynx, trachea and 

 bronchi show congestion and reddening (catarrh). Some 

 of the other organs (spleen, liver, kidneys) show parenchy- 

 matous degeneration. In the subacute and chronic cases 

 the lesions are caseous foci in the lungs, liver, on the mucosa 

 of the intestine and occasionally on the epi- and endo- 

 cardium. Fibrinous pleuritis is frequent in the chronic 

 form. The joints of the limbs are often involved, showing 

 exudation and more or less marked arthritis. The mus- 

 culature in the chronic form will be grayish in color and 

 flabby. 



