TUBERCULOSIS OF THE RESPIRATORY APPARATUS. 693 



infiltrated lung steadily loses its elastic qualities, the vesicular murmur 

 entirely disappears from the affected regions, and the sounds noted are 

 of bronchial origin. 



Like the first, the second phase may vary in intensity, extent, 

 and in the diffusion or localisation of the tuberculous lesions. 

 Blowing respiration may be noted over different areas, accompanied 

 by sibilant, snoring and migratory mucous rales. The vesicular 

 murmur is exaggerated in the healthy parts, coughing, accompanied 

 by expectoration or followed by swallowing movements, is frequent, 

 the appetite becomes capricious, and the general condition suffers. 

 In this second phase almost the whole of one lung may be diseased 

 and exhibit the signs described. 



The third phase corresponds to the softening of the tuberculous 

 masses, and the formation of ulcers and caverns. The zones of 

 dulness or partial dulness may be more extensive, though cavern 

 formation is usually confined to the anterior or middle lobes. Per- 

 cussion still affords no precise information. 



As the tuberculous masses undergo softening and ulceration, 

 their contents are gradually passed into the bronchi, and ausculta- 

 tion reveals signs indicative of the existence of caverns, which signs 

 vary with the dimensions of the caverns themselves. On ausculta- 

 tion the respiration is always found to have at certain points a 

 blowing character, and it may even develop into a true tubal soufiie. 

 In other areas, where the caverns are merely in course of formation, 

 gurgling sounds are all that are heard, but where true caverns 

 exist there is an incessant cavernous souffle. 



The lesions peculiar to the third phase are seldom seen in prac- 

 tice; because the animals become anaemic, exhausted and cachectic, 

 they are usually slaughtered early. Nevertheless, the third stage occa- 

 sionally develops in an astonishingly short time, six to eight months 

 at most. 



Very frequently the patients, although cachectic and even phthisical, 

 do not yield on auscultation the sounds described as peculiar to the 

 third stage, because the tendency to softening is not very marked in 

 bovine animals. The lungs exhibit massive infiltration, and, whilst 

 pulmonary consumption is not uncommon, the development of caverns 

 is comparatively rare. 



The expectoration or discharge in this third form is puriform, 

 glairy, viscous, and of a dirty-yellow or even greenish-yellow colour. 

 Bacteriological examination reveals the presence of tubercle bacilli 

 and adventitious organisms. 



These conditions are always associated with various complications, 

 and the second and third stages of chronic tuberculosis are frequently 



