XII] 



Brachydactyly 



211 



excellent account of the same peculiarity as manifested in 

 an English family extending over seven generations. In 

 his cases also the same law of inheritance is strictly fol- 

 lowed, the normal offspring of abnormals being always free 

 of the abnormality ; while the abnormals marrying with 

 normal persons produce on an average equal numbers of 

 affected and unaffected children (39 : 32, counting those only 

 whose condition is definitely known). 



There are several physiological questions of importance 

 arising out of this case. First, as to the exact nature of 



Fig. 23. Brachydactylous hands. (After Farabee, 122.) 



the malformation, it seems to be clear that in all abnormal 

 individuals examined the fingers and toes are all alike in 

 being short and in having only one phalangeal articulation. 

 Farabee from his radiographs concluded that a phalanx was 

 definitely absent in all cases, but Drinkwater in the extensive 

 series studied by him proved that in some individuals there 

 is in digits III and IV a distinct representation of the 

 middle phalanx as well as the proximal and terminal. His 

 view is that the basal epiphysis of phalanx 1 1 is absent, and 

 that this absence constitutes the essential malformation. 



142 



