The treatment varies with the conditions present, and must include measures directed to the lesion from which the sinus has originated. The extent and direction of any given sinus may be demonstrated by the use of the probe, or, more accurately, by injecting the sinus with a paste consisting of white vaseline containing 10 to 30 per cent. of bismuth subcarbonate, and following its track with the X-rays (Fig. 35). It was found by Beck of Chicago that the injection of bismuth paste is frequently followed by healing of the sinus, and that, if one injection fails to bring about a cure, repeating the injection every second day may be successful. Some caution must be observed in this treatment, as symptoms of poisoning have been observed to follow its use. If they manifest themselves, an injection of warm olive oil should be given; the oil, left in for twelve hours or so, forms an emulsion with the bismuth, which can be withdrawn by aspiration. Iodoform suspended in glycerin may be employed in a similar manner. When these and other non-operative measures fail, and the whole track of the sinus is accessible, it should be laid open, scraped, and packed with bismuth or iodoform gauze until it heals from the bottom. The _tuberculous ulcer_ is described in the chapter on ulcers. CHAPTER IX SYPHILIS Definition.--Virus.--ACQUIRED SYPHILIS--Primary period: _Incubation, primary chancre, glandular enlargement_; _Extra-genital chancres_--Treatment--Secondary period: _General symptoms, skin affections, mucous patches, affections of bones, joints, eyes_, etc.--Treatment: _Salvarsan_--_Methods of administering mercury_--Syphilis and marriage--Intermediate stage--_Reminders_--Tertiary period: _General symptoms_, _gummata_, _tertiary ulcers_, _tertiary lesions of skin, mucous membrane, bones, joints_, etc.--Second attacks.--INHERITED SYPHILIS--Transmission--_Clinical features in infancy, in later life_--Contagiousness--Treatment. Syphilis is an infective disease due to the entrance into the body of a specific virus. It is nearly always communicated from one individual to another by contact infection, the discharge from a syphilitic lesion being the medium through which the virus is transmitted, and the seat of inoculation is almost invariably a surface covered by squamous epithelium. The disease was unknown in Europe before the year 1493, when it was introduced into Spain by Columbus' crew, who were infected in Haiti, where the disease had been endemic from time immemorial (Bloch). The granulation tissue which forms as a result of the reaction of the tissues to the presence of the virus is chiefly composed of lymphocytes and plasma cells, along with an abundant new formation of capillary blood vessels. Giant cells are not uncommon, but the endothelioid cells, which are so marked a feature of tuberculous granulation tissue, are practically absent.