Anatomical Changes. 219 



the susceptibility of the animal, nor does the care the horses 

 receive or the work they do exert any influence. 



Anatomical Changes. The characteristic lesions of the dis- 

 ease are the hemorrhages in the skin and in the mucous mem- 

 brane, as well as in the subcutaneous and submucous connective 

 tissue, in association with extensive, very marked, edematous 

 swellings. Inflammation and tissue necrosis may develop as 

 secondary processes with swelling of the affected parts of the 

 body.^ 



Upon the cut surface of the edematous swelling the subcu- 

 taneous connective tissue forms a yellow, gelatinous layer of 

 several centimeters thickness, which shows dark red hemor- 

 rhages and in some cases contains cavities filled with purulent 

 ichorous fluid, or with necrotic tissue. The gelatinous infiltra- 

 tion extends also between the muscles while the muscle sub- 

 stance itself appears pale grayish-brown or clay color, and 

 friable, as a result of parenchymatous and fatty degenerations 

 of the muscle fibers. The affected muscles feel greasy to the 

 touch, and are sprinkled with small hemorrhages. In different 

 places small areas of the muscles are necrotic and changed to 

 a clay-like detritus, which sometimes appears dirty brown-red 

 from admixture of blood. Hemorrhages may also occur in the 

 tendons and tendon sheaths, under the periosteum, or in the 

 joints; in the latter the cartilaginous tissue may even become 

 necrotic (Prevost). 



Of the mucous membranes those of the nose, pharynx and 

 larynx become affected in the first place, then those of the stom- 

 ach and the small intestines. The mucous membrane is affected 

 less frequently in the deeper air passages and in the other parts 

 of the digestive tract, as well as in the genital organs. In addi- 

 tion to catarrhal injection and swelling, the mucous membrane, 

 as well as the submucous connective tissue of the intestinal 

 canal, also in the muscular layer and under the serosa, small 

 punctiform or streak-like or even larger hemorrhages may be 

 present. The loose connective tissue surrounding them is always 

 more or less gelatinously infiltrated. Over the larger extravaza- 

 tions the mucous membrane is often necrotic, or after the pale 

 yellow necrotic parts have been thrown off, irregularly formed 

 ulcerations develop which are covered with dirty tissue shreds. 

 In the intestines they may extend to the peritoneum, or the 

 intestinal wall may be perforated and lead to purulent or 

 ichorous peritonitis, while in the nose the ulcerative process may 

 cause a destruction ot the nasal septum. 



Hemorrhages are as a rule present also in some internal 

 organs, especially in the lungs and the spleen, and also under 

 the capsule of liver and kidneys. The lungs may contain hemor- 

 rhagic areas the size of a fist, the cut surface may show spots 

 like those of a tiger's skin, which are the result of blood 

 aspirated into the iDronchi. The spleen is sometimes consider- 



