458 Veterinary Medicirje. 



and the disease becomes permanent. A marked predisposition 

 in certain animals, appears to inhere in the constitntion and 

 proves hereditary in the family (Blain, Lafosse, Cadeac). Ner- 

 vons causes have not been satisfactorily traced in the lower ani- 

 mals, yet the dermatitis of the face and neck caused by the ex- 

 perimental lesion of the cervical sympathetic or its connecting 

 ganglia shows clearly enough how any portion must be affected 

 by disorder of its trophic or vaso-motor nerves. Charcot found- 

 that experimental lesions causing inflammation of the spinal 

 cord, led to trophic changes and finally gangrene of a corre- 

 sponding part of the skin. Babesiu and Israi" injected oil of 

 mustard in one side of the cord, in three dogs, and found in 

 several days a vesicular eruption and atrophy of the skin on the 

 same side, a result they supposed of the myelitis. 



DIAGNOSIS OF SKIN DISEASES. 



Diagnosis. Clip or shave skin. Examine in warmth : skin and mucosae, 

 where uninjured by rubbing, moisture, dryness, color, odor, discharge. 

 Soapy wash. Exudation into skin : pliancy : rigidity : eruption : tender- 

 ness, itching, history, association, feeding, watering, exposure, housing, 

 harnessing, driving. Coincident disease. Prognosis. Microbian derma- 

 tosis, parasitic dermatosis, external irritants, ingested irritants, toxic sys- 

 temic products, constitution, renal disease, movement of joints, harness. 



The thick hairy covering of animals, and the vicious energy 

 with which they often rub, scratch and bite themselves, thus 

 turning simple into extensive and severe lesions, interfere serious- 

 ly with a satisfactory diagnosis. The following precautions are 

 usually demanded : 



I St. Clip the animal close to the skin to allow of careful exam- 

 ination. In some affections, this ma}' be dispensed with, but as 

 a rule it should be followed. What appears to be a circumscribed 

 eruption may be shown to be general, or at least extensively 

 diffused over different regions. Or what was shown only by 

 scurf or scab may be seen in its earliei and more characteristic 

 stage as erythema, papule or vesicle. It may even be desirable 

 to shave the affected part, care being taken, not to slice off the 

 characteristic papules, etc. 



