TUBERCULOSIS OF THE LUNGS. 347 



of smaller foci, or may be diffuse from the first and involve 

 even an entire lung. 



The sputum is usually intensely foetid. 



THE INFECTIVE GRANULOMATA. 

 TUBERCULOSIS OF THE LUNGS. 



The pathological changes in the lungs produced by the 

 tubercle bacillus vary somewhat with the different modes of 

 infection, whether through the respiratory passages, the blood 

 or lymph channels ; also with the number and virulence of the 

 bacilli, and more especially with the ability of the patient to 

 withstand their invasion. This last depends not only on the 

 state of one's general health, but also on one's inherited ten- 

 dencies toward the disease, the importance of which cannot be 

 overestimated. Just what is transmitted to an individual 

 who inherits a predisposition to tuberculosis cannot be stated 

 further than that there is a soil markedly favorable to the 

 growth of the germ. 



Besides the characteristic lesion the histological tubercle 

 which is distinctive of the pathological changes produced 

 by the tubercle bacillus, these organisms are capable of excit- 

 ing tissue-changes quite similar to those of ordinary simple 

 inflammation. As in simple inflammations, the more intense 

 the irritant the more prominent the phenomena of cellular and 

 serous exudation, while in inflammations of longer duration 

 and less intensity the characteristic feature is the tendency 

 toward organization and production of new fibrous tissue; so 

 some tubercular inflammations are characterized by exudations 

 and others by proliferative changes. 



When the bacilli gain access by, and are distributed through 

 the medium of the bronchial tubes in large numbers, the lesions 

 are not so sharply circumscribed as they are when the organ- 

 isms are deposited from the bloodvessels here and there in the 

 pulmonary tissue in small numbers nor are they of the same 

 productive type, but are characterized by more extensive 

 exudation and a greater tendency to coagulation-necrosis, 

 caseation, and the involvement of larger areas. 



In the bronchogenic tubercular inflammations of the lungs, 

 in some instances there is a tendency for the areas of pneu- 



