In common with all other branches of medicine, dermatology has felt the result of modern bacteriologic investigations. The brilliant discoveries of Koch, the father of bacteriology, have shattered many idols and put a different aspect upon many things. The advances wrought have been so enormous as to thoroughly have revolutionized some matters. The etiology and pathology of many diseases have been cleared up and the way leading to the elucidation of many mooted questions pointed out.
Lupus vulgaris is one of the questions upon which the search-light of bacteriology has fallen with most beneficial effect. Prior to Koch's time its etiology and pathology were misunderstood. Now nothing is more surely established in medicine than that it is a tuberculosis of the skin. The crucial test of inoculation with pure cultures and with tubercular matter proved the identity of lupus vulgaris and tuberculosis. It is true that animals were successfully inoculated