56 CLINICAL DIAGNOSTICS. 



the papules arc covered by vesicles filled with a clear, tenacious 

 fluid (eruptive stage). In the next few days the contents of the 

 vesicles become turbid, forming pustules (suppurative stage); then 

 drying of the pustules to a solid crust (exsiccative stage). When 

 the crusts fall off a small depressed cicatrix (pit) remains. During 

 the eruption there is fever, loss of appetite, etc. Course about 3' 

 weeks. [Mortality 10 to 50%]. 



3. Canadian horse pox. A contagious pustulous exanthema 

 limited usually to the saddle and harness rests. Perio^d of incuba- 

 tion 2 to 3 days. A few isolated prominences of the size of a half 

 dollar appear, the hair on them is erect and gathered into tufts. 

 The contents of the bullae becomes purulent, erupts, dries to a 

 brownish-yellow solid crust. Caused by a bacillus measuring 2u, 

 which admits of staining with fuchsin. 



4. Urticaria (nettle rash) is a peracute exanthema which is 

 characterized by its sudden appearance. Tumefactions from the 

 size of a pepper-corn to that of a hand or saucer come upon the 

 neck, head, inner surface of the hind limbs and on the body. They 

 are prominent, flat, soft, warm, the iiair upon tiiem standing erect; 

 itching is rare. Urticaria of swine is to be looked upon as a mild 

 form of erysipelas. % 



V. G e n e r a 1 D i s e a' s e 5 which Affect the Skin. 



1. Purpura hemorrhagica (morbus maculosus) is an acute in- 

 fectious disease (an intoxication) characterized by the appearance 

 in the various organs of the body, of multiple hemorrhagic centers 

 of varied size. In the absence of complications, the disease is 

 unattended by fever. On the mucous membranes of the nasal pass- 

 ages blood spots are seen, more rarely they occur in the conjunc- 

 tiva and buccal mucous membranes. In the skin and subcutis of 

 the lips, cheeks, and nostrils, appear hard, inflammatory, edema- 

 tous swellings from the size of a pigeon's egg to that of a hand 

 (larger by confluence), causing the head of the horse afflicted to 

 resemble that of a hippopotamus. The extremities also swell, the 

 swellings terminating abruptly at the stifle and the elbow. There 

 is a diffuse edema of the lower abdomen; hemorrhage in the 

 internal organs. Breathing is labored and stentorious from the 

 mechanical obstruction (swelling) to the entrance of air into the 

 upper respiratory passages. There is difficulty in deglutition, colic 

 symptoms, and impaired locomotion. When the disease has existed 

 for several days, the temperature increases. [Course atypical, 6 to 

 21 days. Mortality about 50%]. 



