PHTHISIS. 121 



were — shrunk and dry and hard and tough, and par- 

 ticularly towards their borders; in others, they assume a 

 dull, tarnished, reddish-brown aspect, and are hepatized." 

 These, however, ought not to be considered as examples of 

 phthisis. " The development of tubercle in the lung," says 

 Laennec, '' is, I think, the only kind of phthisis which we 

 should admit;" and if we would avoid confusion of names and 

 pathological differences, we cannot do better than sub- 

 scribe to this demarcation. 



The development of tubercles in the lungs or other 

 organs, occurs, according to Bayle and Laennec, under two 

 principal forms : — that of insulated bodies j and of interstitial 

 injection or infiltration. "Each of these presents several 

 varieties, chiefly relative to the different degrees of develop- 

 ment. The insulated tubercles present four chief varieties, 

 which I shall denominate miliary, crude, granular, and 

 encysted. The interstitial injection of tuberculous matter, 

 or tuberculous infiltration, offers in like manner three 

 varieties, which I term the irregular, the grey, and the yellow. 

 Whatever may be the form under which the tuberculous 

 matter is developed, it presents, at first, the appearance of 

 a grey semi-transparent substance, which gradually becomes 

 yellow, opaque, and very dense. Afterwards, it softens, and 

 gradually acquires a fluidity nearly equal to that of pus : it 

 being then expelled through the bronchi, cavities are left, 

 \Tilgarly known by the name of ulcers of the limgs, but 

 which I shall designate tuberculous excavations.^' — Laennec's 

 Treatise. 



Both or these forms of tubercles are found in the 

 lungs of horses. The miliary tubercles — which in their 

 progress, by coalescence and conversion into one yellowish 

 homogeneous mass, afterwards become the crude tubercle — 

 are the kind commonly discovered in horses who die of 

 phthisis : round or ovoid in figure, solid, firm, and uniform 

 in substance, or exhibiting in their centres yellow or white 

 spots, or else softened altogether in their consistence, 

 according to the progress they may have made towards 

 maturation. Now and then it happens, from coalescence 



