PHYSICAL CHARACTERS IN MAN 8i 



their normal relatives. They are engaged in un- 

 skilled labour, while their normal relatives include 

 farmers, grocers, etc. In a wild tribe where personal 

 defence with weapons is a necessity, brachydactylous 

 individuals would probably not survive. 



In several papers Drinkwater has made a careful 

 anatomical investigation of brachydactylous hands 

 and feet, including radiographic studies. The con- 

 dition applies equall}^ to fingers and toes, and is 

 accompanied by short stature. In the digits he 

 showTd that the middle phalanx is very short, and 

 has become ankvlosed to the base of the terminal 

 phalanx. Hence the second phalanx is rudimentary, 

 and at a certain stage of development it unites with 

 the terminal phalanx. The most important feature 

 is the absence of the epiphysis (terminal cartilage, 

 which becomes ossified) at the base of the second 

 phalanx. The epiphysis may also, perhaps, be 

 missing in some cases from the third phalanx, the 

 second and third phalanges consisting at first of a 

 single piece of cartilage. The metacarpal (wrist) 

 bones are also more or less abnormal, but the meta- 

 tarsal (instep) bones are unaffected. This abnormal 

 f amity was ver}^ prolific, the number of children in 

 nine families averaging eleven each . A normal woman 

 had forty-five descendants, while a brachydactylous 

 woman in the same famity had ninety-nine descendants . 

 The numbers in successive generations show that the 

 condition is on the increase, and that there is no 

 chance of it becoming extinct so long as the brachy- 

 dact^dous members continue to marry. For some 

 unknown reason the}^ do marry more frequently than 

 their normal sisters. 



The essential feature in brach3^dact3dy is, then, the 

 absence of the epiphysis at the base of the second 

 phalanx, with subsequent ankylosis of the second and 

 third phalanges. The fingers are about half the 



