INHERITANCE OF DIGITAL MALFORMATIONS 

 IN MAN. 



A great deal has been written concerning the abnormities 

 of the hands and feet, and numerous cases of polydactyHsm, 

 syndactyhsm, ectrodactyhsm, and macrodactyhsm have been 

 recorded; but, very few cases of hypophalangia or hyperpha- 

 langia have ever been noted. The following case of hypopha- 

 langia, or diminution in the number of phalanges, came under 

 my notice a few years ago in Pennsylvania. After careful 

 examination the anomaly w^as found to be interesting not only 

 as a case of anatomical variation, but also as a study in heredity. 

 All the digits of all extremities of thirty-seven persons are 

 affected and the anomaly is inherited in conformity with Men- 

 del's law for five generations. Measurements, tracings, photo- 

 graphs, radiographs, plaster casts, and complete genealogical 

 tables, were made.* 



As shown by the photograph (Plate xxiii), the people ap- 

 pear perfectly normal in every other respect and seem to suffer 

 very little inconvenience on account of the malformation. The 

 ladies complain of but one disadvantage in short fingers, and 

 that is in playing the piano; they cannot reach a full octave 

 and hence are not good players. Among the men are farmers, 

 mechanics, business men, and school teachers. One man is 

 at the head of a commercial school and a very excellent penman ; 

 another is catcher for the city baseball team. The hands and 

 feet have the normal number of digits and the digits have the 

 normal proportions, each to each. The thumbs and great toes 

 have the normal number of phalanges, but the first phalanx 



*I acknowledge my especial obligation to Prof. F. \V. Putnam under whose direc- 

 tion this study was carried on. 



(69) 



