90 MARRIAGE AND HEREDITY 



under unequivocal consumption." Haller, the Swiss 

 physiologist, gives an account of a web-footed family 

 descended from a mother in whom that configuration 

 existed. The American calculating boy, Zerah Col- 

 burn, belonged to a six-fingered and six-toed family, 

 the peculiarity having in this case been transmitted 

 through at least four generations. Sir Thomas 

 Watson cites two cases of the kind occurring in his 

 own practice — one that of a musical composer, who, 

 like his father, grandfather, and great-grandfather, was 

 web-footed; the other that of a gentleman who, having 

 six fingers, was constrained to admit the paternity, 

 otherwise doubtful, of an illegitimate child similarly 

 deformed. It is impossible to treat such cases as 

 coincidences. Suppose the proportion of web-footed 

 men in Loudon were as high as 1 in 20,000 ! 

 Against the recurrence of the malformation in the 

 same family, the arithmetical chances would be — for 

 a grandson 20,000 times 20,000, or 400,000,000 to 1, 

 and for a great-grandson 8,000,000,000 to 1. In 

 point of fact web-footedness shows a marked tend- 

 ency to run in the blood. 



Peculiarities affecting one or two members of a 

 family, and not traceable to either father or mother, 

 have probably come down from some ancestor in a 



