IJ 



The Journal of Heredity 



abnormal in Table 3. The ratios here 

 tabulated _show that the metacarpals 

 of the abnormal hands are longer in 

 proportion to their first phalanges 

 than are the average of the metacar- 

 pals of the normal hands. The meta- 

 carpal of the abnormal thumb is ac- 

 tually about one-seventh longer than 

 the average of the five normal first 

 metacarpals. The last phalanx (Pha- 

 lanx 2) of the thumb, however, is al- 

 most one-half shorter than the cor- 

 responding joint of the normal thumb. 

 It is because of this fact that the 

 thumb appears so short when com- 

 pared with a normal thumb and, more- 

 over, it is this short phalanx which 

 is inherited in this family. It ap- 

 pears also that the second phalanx of 

 each of the digits of the abnormal is 

 relatively shorter than those of the 

 normal. Compensatory regulation oc- 

 curs in the appearance of the fingers, 

 since the extra length of the meta- 

 carpals is balanced partially by the 

 short phalangeal joints. The last pha- 

 lanx of the abnormal digits bears no 

 definite relation to the last phalanx 

 of the normal, since it is sometimes 

 longer and sometimes shorter in re- 

 lation to its first phalanx. 



History of the Short-Thumbed Family 



The record of these short thumbs, 

 according to the writer's information 

 begins with a woman (Abnormal 1) 

 who has long been dead. Her daugh- 

 ter (Abnormal 2) when 78 years of 

 age, said that she well remembers 

 that her mother had short thumbs 

 on both hands and, moreover, that 

 both she and her mother always used 

 es])ecially short needles in sewing, be- 

 cause long ones would break in their 

 hands. This peculiarity is correlated 

 with shortness of thumbs. 



The following is a brief record of 

 the occurrence of the character in this 

 family : 



Abnormal 1, a woman, married a 

 normal man. She had two abnormal 

 children (Nos. 2 and 3), two normals, 

 and four who died as infants. 



Abnormal 2, sister of Abnormal 3, 



THE OLDEST OF THE SHORT 

 THUMBS 



Figure 10. The woman designated Ab- 

 normal 2 is now nearly eighty years old. 

 and remembers well that her motlier had 

 short thumbs, for they both had to use espe- 

 cially short needles in sewing. Beyond this 

 it has been impossible to trace the character, 

 but the evidence indicates that for five 

 generations it has been inherited as a Men- 

 delian dominant. 



married a man with normal hands. 

 Her offspring were two abnormals 

 (Nos. 4 and 5), five normals, and 

 three who died in infancy. 



Abnormal 3, daughter of 1, was 

 married to a normal man. They had 

 one abnormal daughter (No. 6) and 

 two children who died as infants. 



Abnormal 4, son of 2, married a 

 normal woman, and they had one 

 abnormal child (No. 7). and two 

 other children who were normal. 



Abnormal 5, daughter of 2, mar- 

 ried a normal man. This pair pro- 

 duced one abnormal daughter (No. 8) 

 and four normal children. 



Abnormal 6, daughter of 3, married 

 a normal man. She had two abnormal 

 sons (Nos. 9 and lO) and one normal 

 daughter. 



Abnormal 7 is unmarried. 



