The conservative treatment of flat-foot and of pes cavus is based upon frequent adjustment of the support, gradual correction, and well-chosen gymnastics. Each component of the deformity must be taken care of during the modeling. The noteworthy feature in the construction of the support described is the employment of the dynamics of gait for correction. With this type of support pressure is distributed over the largest possible surface of the sole, but certain portions of the foot are unsupported in order to permit activity of the muscles of the sole,—particularly of the flexor hallucis longus and the peroneus longus. The type of the support always remains the same; it is merely adapted to the individual foot and to the factors which compose the deformity.