DISEASES OF THE SKIN AND SUB-TISSUES. 297 



Purpura Hemorrhagica (" Scurvy "). 



A disease not unfrequently makes its appearance among horsea 

 termed purpura hemorrhagica, known in human practice as the 

 " purples." It consists of congestion (extravasation) blood of and 

 effusion of serum (water) into the cellular tissue. The disease 

 probably owes its origin to a depraved condition of the blood. 



Symptoms. — On making an examination of the affected animal, 

 we find that the cellular tissue, in various parts of the body, is 

 distended with serum and blood. Local swelling will appear in 

 various parts of the body, more particularly about the face, lips, 

 and limbs. The disease also affects internal parts. Blood is 

 sometimes passed with the urine and feces ; respiration is embar- 

 rassed ; the heart palpitates, and abnormal cerebral symptoms set 

 in. In the human subject the disease is considered strictly as a 

 hemorrhage. Small round spots appear on various parts of the 

 body and legs, of a dull crimson or purple color. Pressure upon 

 them does not efface the color, nor render it fainter, as it does that 

 of common inflammatory spots of the skin. There is scarcely any 

 prominence of the purple stigmata; but they are sometimes inter- 

 mixed with livid blotches, with appearances exactly resembling 

 bruises, and they undergo, before they disappear, the same changes 

 in color which attends the disappearance of a bruise. In fact, the 

 anatomical condition of a bruise is exactly the same, with the dif- 

 fused condition as in purpura. In each case the color is the result 

 of echymosis (effusion of blood beneath the skin). 



In the human subject, also, the disease is not confined to the 

 skin. Watson informs us that " the spots are not confined to the 

 skin, nor to the subcutaneous tissues, but are found, occasionally, 

 upon all the internal surfaces also, and within the substance of 

 the several viscera (internal organs of the body). I have seen 

 these purple spots in the mucous surface of the mouth, throat, 

 stomach, and intestines; in the pleura and pericardium; in the 

 chest; in the peritoneal investment of the abdominal organs; in 

 the substance of the muscles, and even upon the membranes of 

 the brain and in the sheaths of the large nerves, and I have known 

 them to be accompanied with large extravasations of blood in most 

 of the vital organs of the body." 



The same appearances have been observed in equine autopsies, 

 •vliich accounts for the immobility and deranged condition of all 



