10 ESSAYS ON HORSE SUBJECTS 



it can be reduced to a small one. Many breeders 

 use a sire from convenience or from some quality 

 he possesses, such as speed, action, style or dispo- 

 sition, knowing they are taking a chance of per- 

 petuating some tendency to unsoundness that 

 he possesses. Favorite mares are also bred, with 

 a disregard to the well-established principle that 

 "like begets like," even when they are the victims 

 of hereditary unsoundness or a strong predisposi- 

 tion to it. The successful breeder must divest 

 himself of all sentiment and be capable of appre- 

 ciating all defects which constitute predisposition 

 to unsoundness. Of the predisposing causes, de- 

 fective formation is the most fertile one. The 

 predisposition to navicular disease is hereditary. 

 Horses with narrow, deep heels are predisposed 

 to it. Some observers may say: "But look at 

 the large number of horses one sees with narrow, 

 deep heels that have not got navicular disease." 

 Of course, such an argument is fallacious, as 

 there may be many compensating conditions that 

 will tend to neutralize the tendency to this disease 

 in some subjects. A horse with the formation of 

 foot described, even although he is subjected to 

 the exciting causes of hard, fast and steady work, 

 and irrational and infrequent shoeing, may be en- 

 dowed by nature with a very light step. Nothing 

 tends to prevent "wear and tear" of the legs and 

 feet like light stepping. Here, then, is an ex- 



