The absence of one or more of the normal clefts between the fingers or toes is a common congenital deformity, and, like most of the other inherited defects of the parts, is often transmitted by descent, and associated with other malformations. Syndactyly presents all varieties in extent and degree. Most frequently two neighbouring digits are joined together by a web of integument involving the whole or a portion of their length, but in some instances the connecting material is much thicker, and in the most extreme cases even the bones and joints are fused, leaving nothing but a furrow to indicate the line of union. (Fig. 17, Nos. 16 to 19.) Treatment is rarely necessary in the case of the foot, and in the hand is practicable only when the band of union is cutaneous or cellulo-cutaneous. If the web is composed only of a thin double fold of integument it is sufficient to divide it, provided that a return of the condition is prevented from taking place through union of the raw surfaces at the root of the web. This was formerly effected in the slighter cases by a preliminary perforation of the base of the fold, and the insertion of a piece of gold wire until a cicatricial canal has been established—as in piercing the lobule for the suspension of an ear-ring—and the same end may be gained after the division by putting a small epidermic graft upon the angle. Zeller’s flap method is, however, the best. A small triangular flap is cut from the dorsum of the hand with its base opposite the heads of the metacarpal bones, its apex at the level of the first inter-phalangeal joint. This being dissected up and reversed, the whole length of the web is divided. The apex of the flap is then brought forwards between the separated digits into the proximal end of the cleft, and fixed to the cut edge of the palmar integument. When the membrane is very thick, and the bones are drawn close together, a more complicated proceeding is required, and the ingenious method of Didot may be employed. A longitudinal incision is carried through the whole thickness of the integument along the middle of the dorsum of one of the two united fingers, a second along the middle of the palmar aspect of the other finger, and by dissection each digit is made to furnish a rectangular flap to cover in the raw surface of its neighbour. The division of the tissue left after raising the flaps must be made with great care, in order to avoid injury to the digital nerves. ECTRODACTYLY.