Little information is gained regarding the tertiary lesions of yaws from studying textbooks of tropical medicine. It is my purpose in this paper to describe the more common tertiary lesions encountered in this disease. I believe with Howard1 that these tertiary manifestations are of the greatest importance; that they are mutilating and invaliding; and that they may last for years, thus predisposing the subject to the ravages of secondary diseases. Howard, speaking of tertiary manifestations, says: The question is obviously one of the greatest importance in tropical hygiene. Yaws is a widely spread disease and in some parts of the tropics it is almost universal. In its early stages it is a loathsome but not very severe or fatal complaint. If there is no tertiary stage, yaws is not responsible for much invaliding or mortality in the negro race. If, on the other hand, the alleged tertiary stage does