The reaction of the tissues at the site of the first implantation of tubercle bacilli, with the adjacent involved lymph nodes, constitutes the so-called primary complex of tuberculosis. It has been thoroughly described by Ghon,1 whose name the lesion bears, and substantiated by many pathologists and clinicians. Although all the facts concerning the first implantation of tubercle bacilli in man are not known, the histologic characteristics and subsequent history of the "Ghon tubercle" have furnished a splendid starting point for the life history of tuberculosis in a given patient. The majority of first infections, to be sure, occur in childhood, but may occur in the adult. The primary complex is not limited to the lung. Inoculations of the intestinal, nasopharyngeal or genital mucosa, with inflammation of the regional glands, have been frequently observed, and more recently examples of initial infection through the skin have been found,