Abnormalities of the digits occur under a great variety of forms, and with such frequency that most medical men interested in the subject are more or less familiar with them.

In studying such cases one cannot fail to be struck with the fact that, although the tendency to abnormality may be inherited, the inheritance is not always “true,” i.e. the precise form is not accurately reproduced in the offspring. Especially, perhaps, is this the case where the abnormality consists in a deficiency of digits. One individual of a family may have four fingers, another three, and another two, or even one, and that one very imperfect. Such cases have often been recorded (see B.M.J., 1886, vol. ii. p. 976).