A systemic overgrowth of bones and skin may be caused by the abnormal function of certain endocrine glands, such as the anterior lobe of the hypophysis and the gonads. While certain characteristic forms, like acromegaly and gigantism, are clearly recognizable, other anomalies are less well defined. This paper is devoted to the description of a disturbance in growth which is characterized by clubbing and squaring of the extremities, thickening of the skin over the face, scalp and extremities, and deformities of the long bones and their periost. Isolated descriptions of this condition have been reported under a variety of names—pseudoacromegaly, acromegalism, cutis verticis gyrata with acromegaly, pachyacria, megalia cutis et ossium, generalized hyperostosis andpachydermie plicaturée avec pachypériostose des extrémités.They all, however, deal with one and the same condition, which can and should be clearly differentiated from similar but unrelated conditions, particularly acromegaly, leprosy and pulmonary osteoarthropathy (Marie). Because