THE LUNG PLAGUE. 21 



the lung, which is usually smooth and glistening, is rough, of mottled color, and with more 

 or less marked papillary or warty-looking eminences. These are the vascular offshoots of the 

 membrane feeding the deposit around, and in time the process of growth and formation of vas 

 cular or blood-carrying tissue may lead to as solid a connection between the lung and the 

 sides of the chest as between healthy tissues. Such complete development is seen only in 

 very chronic cases, or animals that have recovered from the disease. 



The fluid around one or both lungs varies in amount from a few ounces to several 

 gallons. At times it is tolerably clear when warm, and gelatinizes on cooling. At others 

 it is difficult to separate it from the shreds of lymph and false membranes in the meshes of 

 which it is held. PUK cells frequently abound in it, and it assumes in a few cases the 

 character of pus. It is especially purulent when abscesses have formed in the gangrenous 

 lung tissue, and an opening has led to communication between the lung tissue and the 

 pleural sack. Under these circumstances, the fetor noticed on opening thechest is intolerable- 



On removing the lungs, great variations in extent, but uniformity in essential appear 

 ances, of disease exist. 



In recent and mild cases, one lung is found affected. Its surface may be smooth from 

 the absence of deposit around it. Parts of the organ are collapsed, as in health, and the 

 usual normal pink color is noticed. The affected part is swollen, hard, and mottled. On 

 cutting into this, the older diseased portions present a very peculiar marbled or tessellated 

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

 tween the lobules is of a yellowish red, more or less spotted with red points, but sometimes 

 of almost pure yellowish white color. 



The more recent deposits are distinguished mainly by a lighter red color of the thick 

 ened lobules, and there are gradations from this condition 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, the extent of solidified and darkened lung increases, and 

 portions of the lung tissue lose more or less the marbled appearance, from the blood-stain 

 ing of the interstitial deposit. The consolidation of structures advances so that the blood 

 vessels are obstructed, the diseased lung loses all means 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 admissions 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. The great tenacity of a yellow 

 ish white deposit around a marked marbled 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 solidified deposit in a diseased lung 



