That there has been much inherited variation in the horse cannot be
doubted, when we reflect on the number of the breeds existing throughout
the world or even within the same country, and when we know that they have
largely increased in number since the earliest known records. (2/10.
Godron, 'De l'Espece' tome 1 page 378.) Even in so fleeting a character as
colour, Hofacker (2/11. 'Ueber die Eigenschaften' etc. 1828 s. 10.) found
that, out of 216 cases in which horses of the same colour were paired, only
eleven pairs produced foals of a quite different colour. As Professor Low
(2/12. 'Domesticated Animals of the British Islands' pages 527, 532. In all
the veterinary treatises and papers which I have read, the writers insist
in the strongest terms on the inheritance by the horse of all good and bad
tendencies and qualities. Perhaps the principle of inheritance is not
really stronger in the horse than in any other animal; but, from its value,
the tendency has been more carefully observed.) has remarked, the English
race-horse offers the best possible evidence of inheritance. The pedigree
of a race-horse is of more value in judging of its probable success than
its appearance: "King Herod" gained in prizes 201,505 pounds sterling, and
begot 497 winners; "Eclipse" begot 334 winners.

Whether the whole amount of difference between the various breeds has
arisen under domestication is doubtful. From the fertility of the most
distinct breeds (2/13. Andrew Knight crossed breeds so different in size as
a dray-horse and Norwegian pony: see A. Walker on 'Intermarriage' 1838 page
205.) when crossed, naturalists have generally looked at all the breeds as
having descended from a single species. Few will agree with Colonel H.
Smith, who believes that they have descended from no less than five
primitive and differently coloured stocks. (2/14. 'Nat. Library, Horses'
volume 12 page 208.) But as several species and varieties of the horse
existed (2/15. Gervais 'Hist. Nat. Mamm.' tome 2 page 143. Owen 'British
Fossil Mammals' page 383.) during the later tertiary periods, and as