10 Ji'LY^ 1918.] Hereditary Unsoimdness in Horses. 427 



possible, therefore, that this 2.1 family is either sound or one in which 

 unsoundness is a diminishing factor. A general survey of the family 

 supports the former possibility, for it will be seen that the unsoundness 

 noted is scattered through the many sub-families recorded, and most of 

 the dams that can be traced are from unsound lines. The transmission 

 of unsoundness through the dams is especially noticed in the next 

 generation, where we find that 83 grandsons were examined, and 20.5 

 per cent, found unsound. Though the breeding of many of these 

 unsound animals cannot be traced through their dams to horses recorded 

 in the tables, the following records suggest that their unsoundness hasi 

 come from the dams' side : — 



The dam of 2.164 was by 3.18. He was not examined — two of 



his progeny were, and both were unsound. 

 The dam of 2.165 was by 17.2, not examined; he left 77 per 



cent, unsound out of 9 examined. 

 The dam of 2.10301 was by a son of 3, already referred to as 



a sire of a most unsound line. 

 The dam of 2.103008 was by a son of 6. 21 per cent, of the 



progeny of 6 were unsound. 

 The dam of 2.1030007 was by 7.231, and the granddam by 4.13, 



which left 38 per cent, unsound descendants. 

 The dam of 2.10300006 was by 2.1, the granddam by 22, whose 



blood appears frequently in unsound pedigrees. 

 The dam of 2.10300009 was by a son or grandson of 1. 

 Four of the members of this generation found unsound are by 2.102, 

 himself unsound, and two of them, viz., 2.1023 and 2.1024, are out of 

 mares by 1. Thus very strong evidence as to the source of the unsound- 

 ness can be given in the majority of the sideboned grandsons of 2.1. 



Among the great-grandsons, 19 per cent, were unsound; and, again, 

 evidence of unsoundness being transmitted from the dams is strong. 



2.1013 and his descendants are evidently a sound line ; only one son, 

 2.101303, was sideboned, and this at 3 years old. His dam was by 

 1.003111, an unsound horse. 



2.10414 was from a mare by an unrecorded grandson of 3.1; the 

 recorded grandsons show 40 per cent, unsoundness. 



2.10231 and 2.10234 are by the unsound sire 2.1023, carrying the 

 blood of 1. 



2.1031 is another branch evidently sound. There are 2 unsound 

 sons. One, viz., 2.10316, was from a mare by 1.19, which was very 

 unsound; while 2.10315 was from a mare by 9.521, which, though 

 no unsoundness was discovered in the few of his descendants examined, is 

 a member of a family showing 21 per cent, of unsoundness. 



The next family in this generation worthy of note is that of 2.1032, 

 himself sound at ten years of age. He left 17 sound and 9 unsound sons ; 

 20 sound and 3 unsound grandsons ; 2 of the latter are by unsound sires, 

 whilst the sons which are unsound show the following breeding on their 

 dam's side. 



The pedigree of the dams of 2.10325, 2.1032004, 2.1032007, and 

 2.1032008 is incomplete, but the remaining unsound horses of this branch 

 show breeding as under: — 



The dam of 2.10326 was by 3.1005, a member of an unsound 

 family, which left 43 per cent, of unsound progeny. 



