INFLUENZA IN HORSES. 217 



rounded, or angular patches, and even sometimes in a diffuse manner. 

 These patches are firm to the touch, hhick with a slight tinge of red, 

 and rise abruptlj' to a variable height above the level oH the surrounding 

 healthy lung. Like dropsy, it is most frequent toward the lower 

 borders of the lungs, and, like that, arises from disease of the valves of 

 the left side of the heart, or the altered state of the blood, but at times 

 also from a diseased and softened state of the pulmonary blood-vessels, 

 which predisposes them to give way. 



Gangrene of the lung is fortunately rare. It is recognized by the 

 bloodless, hardened appearance of the tissue, with bluish, greenish, or 

 other metallic tints, or it may be deliquescent, and with a most repul- 

 sive odor. Hepatization is seen mainly about the roots of the lungs or 

 near their lower border. In its early stages the lung is consolidated by 

 a semi-solid infiltration, which drains out when it is cut in thin slices 5 

 later it has a firm, dry, granular appearance, like the substance of liver, 

 easily gives way to the pressure of the finger, does not crepitate nor col- 

 lapse, and sinks in water. It is mainly of a dull deep-red color, varying 

 to a violet. If suppuration has ensued, this changes to a gray color, 

 and drops of pus exude from the freshly-cut surface. The heart is 

 blanched and softened, and sometimes contains clots firm enough and 

 sufficiently adherent to the valves to imply their existence during life. 

 In a recent post-mortem examination of a horse which had suffered from 

 the most agonizing difficulty of breathing for thirty-six hours before 

 death, I found the right ventricle filled with a large clot, very firmly 

 adherent to the tricuspid valve, and composed of superimposed layers, 

 decreasing in firmness from the valves outward. There was some infil- 

 tration around the roots of the lungs, but by no means sufficient to ac- 

 count for the dyspnoea. These clots are often divided into a yellow 

 buffed and a deep-red portion, though at other times and in the more 

 malignant cases they are comparatively diffluent, black, and tarry. The 

 valves of the heart are sometimes found thickened, rough and con- 

 tracted, as the result of inflammation, but chiefly in rheumatic cases. 



In the digestive organs the right sac of the stomach and the small in- 

 testines are unnaturally vascular, and marked with numerous spots of 

 blood extravasation or staining. The glands are often enlarged, the 

 epithelium is easily detached, and slight punctiform erosions are some- 

 times met with, but no distinct ulceration. Petechia? may also be pres- 

 ent on the folds of the peritoneum. The intestinal contents are often 

 mingled with excess of mucus, or even colored with blood. The liver 

 is often enlarged, softened, and friable, and of a pale-yellow hue, with 

 brownish spots. In all cases in which the changes in the blood have 

 been extensive, and, above all, in cases which have merged into jmrpura 

 iKvmorrMgica, the spleen is engorged with blood and increased in size 

 and weight. The kidneys are usually healthy in aspect, though in some 

 instances enlarged and softened. 



The brain is usually found slightly congested, and effusions have been 

 met with in the ventricles, in the arachnoid and sub-arachnoid space. 

 So constant was this lesion during the epizootic of 183G in London, that 

 Charles Clark concluded, after extensive dissections of dead horses, 

 that this was the primary seat of the disease, and that all other mani- 

 festations were simply complications. To these may be added the liquid 

 effusions beneath the skin and between the muscles and tendons in 

 dropsical cases, the inflammations, thickening and redness of tendons 

 and their sheaths, and of joints with the puffy swelling' of joints, and 

 other synovial sacs in rheumatic subjects, and the blood-staining of the 

 inner surface of the skin, the gelatinous exudations and the accumula- 



