40 
Split-Hand and Split-Foot Deformities 
for the transmission of a particular type these relations do not hold. With few 
exceptions each tijpe of foot is found in association with each type of hand. Lastly, 
although in certain families, as in that of Mayer, such a combination as split hand 
and split foot occur together and predominate, yet there are families in which 
many combinations of types are blended. Dealing with the main facts, it may be 
said that when this quadruple deformity, which presents extreme variation of form, 
exists as a hereditary malformation, the constantly occurring similarity between 
individual parts and individual combinations, when taken into account with the 
common tendency to transmit along definite lines, leads to one conclusion, namely 
that in all these families tlie deformity of each individual has tJte same fundamental 
basis ; in fact that the deformity is a distinct entity. 
It now remains to bring into line those cases which have been reported as 
isolated cases ( Bibliography, Section B). At first sight the absence of the hereditary 
hi.story sharply breaks them off from the familial cases so far discussed. There are 
in all, however, only 13 cases of which we can find descriptions or figures, and of 
these eight are not dealt with from the hereditary standpoint at all. In five it 
maybe assumed that the parents were normal but two of these were 
children and the third a lad. In some of the 13 cases there is consequently 
a possibility that the question of heredity was neglected, in others there was no 
opportunity of studying it. In yet other cases the absence of hereditary history may 
have been due to the reticence of the patient; from our experience of the "G" 
family we may say that had we first met certain members of the family now known 
to us, we should have had great difficulty in extracting the necessary information. 
Illegitimacy, several examples of which we have ourselves met, provides another 
possible source of error. Again a certain proportion of the 13 cases are likely to 
have been the first in their family to show deformity*. Lastly it is more than 
possible that a deformed person may have the jDotentiality of transmitting and still 
fail to do so. These considerations lead us to believe that some if not all of the 
isolated cases either actually belonged to deformed families or were by no means 
lacking in the power to transmit the malformation, and there is consequently no 
reason to exclude them upon this score. Moreover, considering their deformities, 
no isolated case occurs in the list wJiich is given which does not find its almost exact 
counterpart in members of the families given in section A. Consequently as there is 
little hesitation in regarding the familial cases as examples of the same entity so it 
is considered that the isolated cases, though vaiying widely, are of the same nature 
and may be classified with them as illustrating a deformity sui generis. 
Having now, as we believe, established! the deformity under discussion as an 
entity, the terminology may be biiefly referred to. So many terms are found in 
* The proportion of orifiinal deformed members to those occurring in the 19 families is approxi- 
mately as 1 is to 8. 
t It is not possible to bring forward the complete evidence in support of this view, as space does not 
permit, liut those who are acquainted with the reports and figures cannot fail to be struck by the close 
similarity of separate cases. The position is iu reality far stronger than it can be made in a general 
outline sketch. 
