1 54 E VOL UTION AND DISEASE. 



considered as distinct animals, having very distinct 

 powers. In order to ascertain this, I took the spurs of 

 hen-chickens and placed them on the legs of young 

 cocks. I found that those which took root grew nearly 

 as fast, and to as large a size as the natural spur on the 

 other leg, which appeared to be a contradiction to my 

 other experiments. Upon another examination of my 

 hens, however, I found that the spurs had grown consider- 

 ably, although they had taken several years to do it ; 

 for I found that the same quantity of growth in the spur 

 of a cock, while on the cock, during one year, was as 

 much as that of the cock's spur on the hen in the course 

 of three or four years, or as three or four to one ; whereas 

 the growth of the hen's spur on the cock was to that of 

 the proper spur of the hen as two to one." 



When a female animal belonging to a dimorphic 

 species assumes male characters, it is truly an example 

 of atavism, or development of transmitted characters 

 normally latent. 



Before leaving this matter it will be useful to indicate 

 to some extent our knowledge as to the frequency of 

 the assumption of male characters by the females of 

 dimorphic forms. In birds there can be no question 

 that very many specimens have been seen and carefully 

 studied, but in the case of female deer putting up antlers 

 the case is very different. On making inquiries of 

 persons likely to have seen such specimens I find it 

 extremely difficult to obtain authentic information, and 

 many of the statements in circulation on this matter 

 have very shallow foundations. One of the most acces- 

 sible specimens is preserved in the museum of the Royal 



