GENERAL PRINCIPLES OF BREEDING. 47 



and feature, and especially the widely-famed 

 beauty of countenance and form, as well as the 

 mental vigor displayed by Cleopatra, the last 

 of the line, have often been quoted as a strong 

 argument against the theory that breeding in- 

 and-in necessarily produces physical deteriora- 

 tion; but a close examination of the line of 

 descent leaves the balance of the argument 

 rather on the other side. Gal ton, in his " Hered- 

 itary Genius," in speaking of this family, says: 



This race of Ptolemys is at first sight exceedingly inter- 

 esting, on account of the extraordinary number of their 

 close intermarriages. They were matched in-and-in like 

 prize cattle; but these near marriages were unprolific the 

 inheritance mostly passed through other wives. Indicating 

 the Ptolemys by numbers, according to the order of their 

 succession, II married his niece, and afterward his sister; 

 IV his sister; VI and VII were brothers, and they both con- 

 secutively married the same sister VII also subsequently 

 married his niece; VIII married two of his own sisters con- 

 secutively; XII and XIII were brothers, and both consecu- 

 tively married their sister, the famous Cleopatra. Thus 

 there are no less than nine cases of close intermarriages dis- 

 tributed among the thirteen Ptolemys. However, when we 

 put them into the form of a genealogical tree we shall clearly 

 see that the main line of descent was untouched by these 

 intermarriages, except in the two cases of III and VIII. The 

 personal beauty and vigor of Cleopatra, the last of the race, 

 cannot therefore be justly quoted in disproof of the evil 

 effects of close breeding. On the contrary, the result of 

 Ptolemaic experience was distinctly to show that intermar- 

 riages are followed by sterility. 



Galton then proceeds to show that nearly all 

 of these incestuous marriages were unfruitful, 



