54 
Proceedings of the Royal Society of Edinburgh. [Sess. 
84 descendants. This equals 42 children from 9 parents (average), which 
can be compared with the 9 parents descended from No. 17. Thus the 
relative fertility of normals and abnormals is as 28 to 42 or as 4 to 6. 
Relative fecundity of men and women (abnormals) : — 
Six married women have had 49 children, an average of 8J. 
Eight married men have had 39 children, an average of 4J. 
The women are clearly much more prolific than the men (amongst the 
abnormals). 
Marriage . — Taking individuals over 23 years of age, and beginning 
at the fifth generation. The following never married : — 
(1) Dead. — Two normals, both descendants of normal parents. Both 
were women. 
(2) Living. — Fourteen normals (9 female and 5 male). 
They are all descended from normal parents. There is not a single 
abnormal individual, either male or female, over 23 years of age, who 
has remained single. There is no record of any intermarriage, either of 
normals or abnormals. 
Childless Marriages . — There are four of these, all living. Two are 
normal women, one is a normal man, and one an abnormal woman. They 
have all been married several years. The abnormal woman is the 
oldest surviving member of the family. 
Origin of Species . — I do not wish to tread on debatable ground further 
than to state my opinion that the existence and perpetuation of individuals 
such as these brachydactyli, who show a marked variation, reproduced in 
several successive generations, seems to support the views of those 
biologists who contend that evolution frequently occurs per saltum, 
and not invariably, as others suppose, by minute and almost imperceptible 
gradations. 
The abnormality of this family is not such as to confer upon the 
individuals any advantage in the struggle for existence, but rather are 
they at a disadvantage, such that, in the wild state, the variety would 
soon be stamped out. It is, however, quite conceivable that an equally 
well-marked beneficial variation might occur, and in that case one 
would expect them to survive. These brachydactyli, in a wild state, 
would have succumbed owing to their inability to use effective weapons 
of offence and defence. But the conditions of modern civilisation are such 
that many individuals, handicapped at birth, are not only able to 
survive, but to perpetuate their defect, even though it tend to deteriora- 
tion of the race. So dominant are the abnormal members of this family, 
that there is little chance of their peculiarity becoming extinct so long 
