XII] 



Brachydactyly 



213 



obviously a close bearing on the nature of meristic varia- 

 tion, but a discussion of that problem is beyond my present 

 scope"^. 



If we were dealing with natural species or varieties a 

 debate might arise on the question whether it is readily 

 to be imagined that so definite a variation could have arisen 

 independently in the two sets of families, in America and 

 England respectively. To those who have experience of 

 variation and who know how large and well defined discon- 

 tinuous variations may frequently be, it will not seem much 

 more difficult to conceive of the repetition of the variation 



Fig. 25. Hands of brachydactylous woman, age 32. A separate ossification 

 can be seen in digit III between the 1st and 3rd phalanges. In the 

 other digits union of this element with the 3rd phalanx has already 

 taken place. (From Drinkwater's unpublished photograph.) 



than of its first occurrence. There is however some plausi- 

 bility in the suggestion that these two families may in 

 reality be one in origin, for it is known that a male abnormal 

 of the 4th generation in Drinkwater's strain did emigrate 

 to America. On the other hand the abnormal first recorded 

 in Farabee's strain was a female in the 5th generation from 



* It must be observed that in view of Drinkwater's facts the variation 

 is not simply meristic in the sense that the digit divides into two joints 

 instead of three. As he himself is inclined to suppose, the case is more 

 probably to be regarded as a homoeotic variation of the digits into the 

 likeness of the hallux and poUex. 



