This deformity results from failure of the bones of the two sides of the face to unite in the process of development. When the difficulty occurs upon one side alone, the patient has single hare-lip. When it occurs upon both sides, the deformity is double. The appearance of this deformity in its different phases is well shown in Figs. 496 to 498. The difficulty seems to be hereditary in some families.

Figs. 496 to 498. Hare Lip.

Figs. 496 to 498. Hare Lip.

It occurs most often in males.

The only remedy is a surgical operation, which consists in paring the edges of the cleft on each side and bringing them together with proper sutures. The operation is generally a very successful one. It should be performed, by preference, sometime between the third month and the period of teething.