On Cross Breeding. 
297 
the human subject too close affinity, such as the intermarriage of 
cousins, tends to mental diseases and consumption ; and we can 
readily imagine that when there is a tendency to such diseases in a 
family, this tendency must be greatly increased by intermarrying 
with a member of the same family. Animals not being subject to 
mental diseases, the observation does not apply to them with the 
same:force, but it is true in a lesser degree. At the same time, 
unless the choice is extremely confined, most of the evils of pure 
bi'eeding can be avoided by careful selection and rigorous weed- 
ing. Examples of pure breeding are familiar to us in the 
admired race-horse, the first-class short-horn, and the South- 
down sheep ; but, so far as purity of breed alone is considered, 
the mountain sheep of Wales, the Highland Scotch cattle, and the 
Shetland or Welch, are equally pure ; but whilst the latter have 
been propagated without care or attention, the former have, by 
careful selection and rigorous weeding, been considerably enhanced 
in value. A striking example of long continued pure breeding 
is afforded by the Leicester flock of Mr. Valentine Barford, of 
Foscote near Towcester, who has the pedigree of his sheep from 
the day of Bakewell in 1783 to the present time, and since 1810 
he has bred entirely from his own flock, sire and dam, without 
an interchange of male or female from any other flock. He 
observes, " that his flock being bred from the nearest affinities — 
commonly called in-and-in breeding— has not experienced any 
of the ill effects asciibed to the practice." His flock is remark- 
ably healthy, and his rams successful, but his sheep are small. 
Let us pause for a few minutes to consider what constitutes 
breed, or rather what is meant by high breeding. We shall find 
that it refers to very different desiderata in different breeds. In 
the thorough-bi'ed horse it signifies a very high development 
of the muscular and nervous systems, accompanied by such 
mechanical structure as when united with it constitutes the 
highest manifestation of speed and endurance. In the ox, how- 
ever, it implies very different qualities, viz., early and rapid 
growth — the development of flesh or muscle on the parts 
most prized for food — a disposition to lay on fat ; these, with 
the possession of the smallest amount of bone consistent with 
strength and health, are the principal characteristics of a well- 
bred animal. Instead of the highly-nervous temperament of the 
race-horse, we have here a quiet lazy disposition ; in fact, a 
lymphatic temperament, by the influence of which the digestive 
organs reign supreme, and convert for the public benefit a given 
quantity of food into the utmost amount of flesh and fat. The 
same observations apply with equal force to the sheep, and in a 
still stronger degree to the pig. A well-bred pig is the incarna- 
