H. Drinkwater 241 



high onlcr ; numy of the members <are professionals, and have university 

 degrees in imisic. In every case they show that whcu-e both parents are 

 nuisical all the children show musical ability. The E. D. and the J. 

 families agree with the theory that musical talent is inherited as an 

 ordinary recessive, like dwarfness in Pisum sativum. Tn the R. 

 pedigree the three children of / = ? are all musical and this is 

 exceptional. 



The chart of the S. D. family shows two branches (or roots). One 

 A contains non-musical members exclusively: the B branch is entirely 

 musical. When both parents are musical all the children art; musical (B). 

 Whi're musical ability is lacking in both parents, all the children lack 

 musical ability (A). The two fiimilies became united by marriage. 

 According to Mendelian theory — i.e. supposing musical ability to be 

 transmitted as an ordinary recessive — the children should all lack 

 musical ability, but as a matter of fact exactly 50 per cent, are musical, 

 and two of them are professionals of great ability. The inheritance is 

 exactly what would be looked for if the father (</) were heterozygous, 

 but from the pedigree he is more probably homozygous. 



The conclusions that one must come to from a study of these 

 pedigrees are 



(1) The inheritance is strictly Mendelian where both parents show 

 the ' recessive ' trait. 



(2) There are too many musical children Wivn, when only one 

 parent (apparently) is musical. 



(3) No satisfactory explanation can be offered for the latter feature. 



(4) Musical sense is probably recessive. 



Joiirn. of Gen. v 16 



