Many have reported cases of isolated disease of the tarsal scaphoid, but, apparently, none have considered their cases from a viewpoint of functional end-results. We wish to report one case from its incipiency to its termination, careful, painstaking treatment being carried out during the interim. Two other cases of undoubted Köhler's disease, which were untreated, are reported in order to demonstrate the function of the scaphoid, its shaping after untreated recovery, and the consequent end-results. The function of the scaphoid is that of a multiple keystone, supporting the weight distributed between the distal ends of the metatarsals, the os calcis and the cuboid. This bone is, therefore, subjected to stress from all sides (except from the superior aspects) when weight is placed upon the foot. We know that any bone, according to an interpretation of Wolff's Law, assumes a shape compensatory to its added function and changes its minute structure to conform, after a definite change in its normalcy. The tarsal scaphoid ossifies from two centers. Frequently the two portions of the scaphoid do not unite. A divided scaphoid is afterwards discovered inadvertently by means of the roentgen ray, and consequently not a great deal of significance is placed upon it. Now comes our theory of the condition first described by Köhler and interpreted by many as due to pyogenic infection. Wolff first explained bone changes following injury to the cartilage between the epiphysis and the diaphysis. We believe—and our belief is substantiated by the following case reports—that an injury to the center of ossification of the scaphoid produces a definite change in the shape of the bone and definite abnormality in its ossification. The accompanying radiograph (Fig. 1) of Case 1 demonstrates that the bony scaphoid is much flattened, but that there is marked space between the scaphoid and the astragalus, and the scaphoid and the internal cuneiform. It demonstrates also that the density of the bony portion is decreased, indicating a lack of normal function of the ossification centers. Therefore the spaces are occupied by cartilages lacking the bone-forming function because of injury to the centers of ossification. The injury to the centers is due not to pyogenesis, but to violence. The pain, local swelling, and redness are easily explained without the consideration of infection. Again, the process occurs only in childhood and would therefore be classed as mechanical rather than infectious. Also, the tarsal scaphoid is the only small bone ever involved in a process of this nature, and when its function is remembered the explanation is simple. Case No. 1. J. C, age five, appeared for examination in July, 1919. Complaint: pain in right foot when active. Examination revealed slight redness and swelling over dorsum of right foot. Temperature normal. Blood count normal. No evidence of any systemic trouble. Family history negative.