38 
Proceedings of the Koyal Society of Edinburgh. [Sess. 
“ dominant ” abnormality or characteristic, the variation of the abnormal 
parent will be reproduced (in the offspring) in approximately 50 per cent. 
Such is the case in this family. The total number of descendants from the 
abnormal parents, beginning at the fourth generation (for in the earlier 
ones the respective numbers are not known), is seventy-five, and of these 
thirty-nine are abnormal s — a result corresponding with what we should 
expect from Mendel’s law. 
Another point in which this family agrees with Mendel’s observations 
is the fact that the children of normal parents are all normal. The 
peculiarity is solely transmitted by a brachydactylous parent, and when it 
once disappears, there is no tendency for it to crop up again in any of 
the descendants. This is shown by the decendants of the female, number 
17, amongst whom not a single abnormal individual has appeared in three 
successive generations. 
This abnormality thus differs in a marked manner from certain 
hereditary diseases, which are known to appear in the children of a parent 
in whom it was latent. 
There are twenty-five abnormals living at the present time in England 
and Wales. I have been successful in obtaining photographs or radiographs 
(or both) of all except the oldest surviving member of the family and four 
very young children. The old woman lives in a rural district, seven miles 
from a town, and she promised to send me a photograph of her hand, but 
up to the present it has not yet arrived. The young children have been 
photographed, but the results are unsatisfactory : they could not be made 
to keep their hands still for a sufficient time to give the desired results. 
The hands have been photographed and X-rayed more carefully and com- 
pletely than the feet, as the abnormality seems more striking in the hands. 
I am greatly indebted to Dr List of the North Stafford Infirmary and 
to Drs Humphrey and Geoffrey Williams for their kindness in procuring 
the radiographs for me. 
The hands and feet, as already stated, are abnormal in each affected 
individual, and the feet are, if anything, more abnormal than the hands, at 
least as regards the digits. The middle phalanx is practically or virtually 
— though not actually — absent from each finger and toe. The metacarpal 
bones are short, and otherwise abnormal, but the metatarsus is scarcely, if 
at all, affected. Nor is the variation limited to the hands and feet, for all 
the individuals, with the exception of young children and perhaps one 
female, are below the average stature, as is shown by a reference to the 
table of measurements. It will be well to study each part in turn in the 
following order : hands, feet, stature, etc. 
