Simple congenital ectrodactyly, like the loss of a larger segment of an extremity, may arise either by intra-uterine traumatism or defective development. Amputation by an amniotic band or a coil of umbilical cord probably explains the majority of the cases, as well as the congenital constrictions sometimes found in the limbs or digits of the newborn child, but the occasional appearance of fingers or toes at the end of a congenital stump can only be accounted for on the hypothesis of a temporary suspension of development in the proximal portion of the stump, and we may assume the possibility of a like origin for the absence of the most distal portions of a member. In some instances an ectrodactyly is complicated with other developmental errors, and may be transmitted through several generations. Attention has been especially drawn to cases of this class in the last few years. Two were recorded in detail in 1886 by Dr. Fotherby[41] and the author,[42] and a third was added five years ago by Messrs. Parker and Robinson.[43] In all of these the defect was traced through three or four generations, selecting in an apparently indiscriminate way a large portion of the members of the family, whilst leaving others exempt. In some individuals all four limbs were attacked, in others the upper or lower only, but usually with a more or less perfect bilateral symmetry. In most cases the ectrodactyly was associated with deformities of the remaining digits, such as syndactyly, hypertrophy, and joint distortions; and where, as frequently happened, the middle digits were imperfectly developed and the others hypertrophied and distorted, the member assumed the appearance of the pincers of a lobster. (Fig. 17, Nos. 11 to 14.) In Dr. Fotherby’s and Messrs. Parker and Robinson’s cases the defects were traced through three generations, affecting sixteen out of thirty-seven descendants in the one and sixteen out of thirty-three in the other; in the author’s case the history extended to four generations, attacking twenty-four out of thirty-six children, and the divergence from the normal state tended to increase with the later scions. As a rule, little or no treatment is called for in this condition, because habit has given the member a good deal of functional utility that surgical interference might injure or destroy; but sometimes, and more particularly in the feet, it is permissible to operate for the purpose of lessening the deformity, as in Messrs. Parker and Robinson’s case, where a plastic operation was performed with much benefit to the patient. BRACHYDACTYLY. Undue shortness of the fingers or toes may occur either as a congenital or as an acquired defect. The congenital form, due to imperfect formation of any or all of the bony elements of a digit (including the metacarpal bone), is insusceptible of treatment except by amputation, should that step be justified by the inconvenience or deformity attached to the defective member.