688 INFECTIOUS DISEASES. 



The lung may be affected to such a degree that it appears incredible 

 that the blood can have been sufficiently aerated to support life. 



The lungs may be transformed into yellowish, caseous, calcareous, or 

 softened masses enveloped in thick, fibrous, resistant walls. The inter- 

 vening pulmonary tissue may be healthy in appearance, or reddened, 

 congested, and sometimes hepatised. 



The pleural, pericardial, and peritoneal membranes may be covered 

 with exuberant tuberculous lesions, like ripe mulberries, in consequence 

 of fusion and massing of the tuberculous growths. The primary 

 tubercles are surrounded with fibrous walls, which granulate when 

 on the surface of a serous membrane, and impart to the membrane a 

 vegetative, sometimes villous appearance, and a colour varying from 

 pink to light or dark red. 



The collective lesions lining the cavities are described by butchers 

 under the significant term of "grapes." In tlie interior of these exu- 

 berant masses, which sometimes form layers an inch or more in thick- 

 ness, the tuberculous lesions undergo the usual developmental changes, 

 that is to say, they become caseated or infiltrated with lime salts, but 

 they do not so readily undergo softening as those of the lung. The 

 parietal and visceral serous membranes readily become adherent at 

 numerous points, setting up union between the lung and the walls of 

 the chest, or the intestine and the walls of the abdomen, etc. 



In the pericardium the vegetations are frequently of a fungoid 

 character. 



Tuberculosis of lymphatic glands sometimes assumes a disseminated, 

 discrete form or that of a diffuse infiltration, or, again, in old-standing 

 cases it constitutes a massive tuberculous conglomeration. In point 

 of fact, the lymphatic glands as such no longer exist, their tissue 

 having undergone total degeneration ; they are represented only by 

 an enlarged, thick, fibrous shell, forming the envelope which encloses 

 caseated and calcareous masses of a more or less soft nature. 



Tuberculous infiltration of the sub-maxillary and sub-parotideal lym- 

 phatic glands interferes with swallowing and breathing, compresses the 

 pharynx, oesophagus and larynx, and deforms the head. 



Compression of the arteries, veins, nerves, etc., at the entrance to 

 the chest may cause various symptoms which are not difficult to inter- 

 pret. The glands at the entrance to the chest and the whole of the 

 anterior mediastinum may form a single mass. Lesions in the pos- 

 terior mediastinum, however, are of even greater importance and 

 explain certain symptoms, such as difficulty in swallowing, spasm 

 of the oesophagus, mechanical contraction of the oesophagus, perma- 

 nent tympanites, etc., for which the state of the lungs alone would 

 not account. 



