ous tuberculosis and may be properly described as a tuberculide. There are other affections of the skin which are commonly associated with the varied symptoms of scrofula and in which the bacillus tuberculosis may be found, but they are clinically distinct, though pathologically related to lupus. The term tubercular, as applied to lupus, was originally used only in a morphological sense, indicating the nodular character of the eruption. It is a singular fact that, while the old term is still
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Fig. 37.—Tubercles forming a ring.
retained in use, science has invested it with a deeper and more definite significance since the discovery in the nodule of the tubercle bacillus.
Lupus vulgaris is an affection which is often seen in childhood, and which, indeed, begins in most cases before the age of puberty. It usually appears in the form of one or more dull red papules upon the cheek or elsewhere. These slowly increase in number and tend to coalesce (Fig. 30). Frequently the older or central lesions disappear by interstitial absorption and an
