THE LUNG PLAGUE. 29 



tlie older diseased portions present a very peculiar marbled or tesselated 

 character. The substance of the lobules is solid and of a dark red color, 

 and the tissue between the lobules is of a yellowish red, more or less 

 spotted with red points, but sometimes of almost pure yellowish white 

 color. 



Tlie more recent deposits are distinguished mainly by a lighter red 

 color of the thickened lobules, and there are gradations from this con- 

 dition to that in which the lobules are but slightly infiltrated with semi- 

 liquid serum, and air still passes more or less into their air vesicles. 



As the disease advances, tlie extent of solidified and darkened lung 

 increases, and portions of the lung tissue lose more or less the marbled 

 appearance, from the blood-staining of the interstitial deposit. The con- 

 solidation of structures advances so that the blood vessels are obstruct- 

 ed, the diseased lung loses all meaus of nourishment, and the older^ 

 darker, and more solid portions become detached, so that they remain 

 as foreign bodies imbedded in cavities in the diseased tissue. The admis- 

 sions of air through the air passages into these cavities by dissolution 

 of the lung tissue, lead to the cavernous sounds which the ear can detect 

 in the living animal, and the broken-up tissue decomposes and induces 

 great fetor of the breath. 



One lung may have several points diseased; each lobe may be affected 

 and little or no communication between the several parts implicated. 

 Tlie great tenacity of a yellowish white deposit around a marked mar- 

 bled center of disease has been said to indicate a certain tendency to 

 limitation by the formation of a capsule, and several encapsulated cen- 

 ters may be found. 



On taking a warm diseased lung, severing the still healthy portions, 

 making incisions into the parts solidified, and suspending them so that 

 they may drain, a large amount of yellowish serum of a translucent 

 character, almost wholly free or more or less tinged with blood, is 

 obtained to the extent of pounds in weight. The amount varies with 

 weight of diseased lung drained. The quantity of this and of the solidi- 

 fied deposit in a diseased lung is so large, that from a normal weight of four 

 or five pounds, a lung attains to ten, twenty, forty, and I have seen one 

 as high as fifty-four pounds in weight. 



AIR PASSAGES. 



The condition of the air passages varies from a condition of perfect 

 freedom down to the diseased portions of lung, to a state in which the 

 mucous membrane is coated with false membrane or solid exudations of 

 lymph. By suitable means it is not difficult to isolate the solid white 

 lymph clogging the terminal bronchial tubes and air vesicles in the con- 

 solidated tissues, but at a distance from these i)arts it is only in some 

 cases that a kind of (;roupy complication exists. I have seen an animal 

 gasping for breath, with its mouth open, nostrils widely expanded, eyes 

 prominent, and visible mucous membranes of a bluish red color j ou 



