CHANCRE is a term formerly used loosely, to designate any sore or ulcer, especially one of a corroding nature or venereal origin. It is now applied almost exclusively to the primary lesion of syphilis, which used to be called a hard, indurated or Hunterian chancre. It appears at the site of inoculation in from one to seven weeks after exposure, and is most commonly found on the external genitals, but sometimes on the lip, tongue and other parts. A small, hard, translucent swelling appears at the infected spot, becomes gradually larger (up to one inch), and often breaks in the centre leaving a shallow ulcer. This lesion is the chancre and represents the first reaction of body tissues to the causative agent, Treponema pallidum. Diagnosis is established by finding the or ganism in scrapings from the ulcer. (See VENEREAL DISEASES.)