MASCULINE FEMININES 257 



which has yielded the great majority of examples 

 of females assuming the characters of the male. 

 It happens that the birds of this order, being the 

 best of all food birds, are the most frequently 

 handled ; whereas in a dimorphic species which 

 is rarely or never handled, it would be strange 

 if the occurrence were detected. A female chaf- 

 finch or bullfinch, for example, might assume male 

 plumage ; but if it did not happen to be in 

 captivity, the change could never be observed. But 

 it is certain that the development of maleness in 

 females is not confined to the gallinaceous birds, 

 for a ten-year-old duck has been known to assume 

 both the perfect winter and summer plumage of 

 the drake. Nor is it confined to birds. In at 

 least two species of deer, hinds have been known 

 to grow antlers, and, as everybody knows, some- 

 thing analogous occurs in the human species itself, 

 varying in notableness from the development of 

 masculine mental attributes to the development of 

 so unmistakably masculine an attribute as a 

 moustache or beard, or both. 



Occurrences of this sort are of high scientific 

 interest for the light they throw on the problem 

 of sex and sex inheritance. In every investigated 

 case it has been found that the development of 

 secondary sexual male characters by the female 

 is associated either with age or with injury to the 

 primary sex characters. The barn-door hens which 

 assume cocks' plumage are almost invariably old 

 birds which are past laying. In many other 

 examples subjected to examination it is found 

 that the fertility of the ovaries has been destroyed 



