The word is used to indicate scales, which are obvious enough on a mere cursory examination. A scaly condition of the skin may be an accidental condition, and simply denote want of cleanliness, or it may be an indication of irritation of the surface, or the outcome of some specific disorder.
Tubercula are small lumps or large pimples, which are hard and circumscribed, and are commonly permanent. Occasionally they undergo slow suppuration, but ordinarily remain as small fibrous tumours, which are of no special significance unless they occur on parts of the body with which the harness is brought into contact, as on the shoulders and back.
Besides these changes in the skin which have been described, there are to be found crusts or scabs which consist of the dried exudation matter discharged from a broken surface. They vary in their appearance according to the character of the discharge, to the drying of which they owe their origin.
Ulcers are well known as complications in certain forms of skin disease. They consist really in destruction of the tissues of the true skin, arising either from simple inflammation, or from a specific disease, as in glanders.
Excoriations are those superficial injuries due to the removal of the cuticle by friction between two surfaces of the skin, or by the act of rubbing, scratching, or biting to relieve itching, or from the pressure of harness.
Having satisfied himself as to the existence of one or more of these morbid conditions, the examiner is in a position to make a preliminary diagnosis, possibly to form also a prognosis, and also to arrive at some conclusion as to the cause of the disease and the principles of treatment.