4(S4 History of the Author's 



consumption at a halfpenny or a penny per lb. less than the Ryeland, Welsh, or 

 South Down. 



But what, in the Leicester breed, is the nature and proportion of the muscular 

 substance, or lean? Exactly what must happen from their age and habits of life. 

 The muscles of young animals are always small. They do not attain their ultimate 

 size till adult age. Whatever may be the vulgar opinion as to the Leicester sheep, 

 at the age at which he is killed he is immature, and his muscles scarcely half grown. 

 Farther, muscles much used, enlarge ; not used, shrink and decay. Hence the 

 leg of a postilion is almost without a calf, while that of a chairman is exube- 

 rantly full. Were the strongest man to keep his arm for a year in a sling, expe- 

 rience shews that the muscles would be reduced to less than half their original 

 solidity and bulk. So wild birds, which are much on the wing, have plump pecto- 

 ral muscles, or breasts ; while those which only walk, and the former, when domes- 

 ticated from the egg, have the breast comparatively thin and flaccid. Examine the 

 muscular substance of a Leicester sheep, and you will find it exactly in the same 

 state. I will venture to assert that the lean of one of those animals at 2^ years old, 

 weighing 25 or 30 lb. a quarter, is scarcely heavier than that of a Ryeland of proper 

 age, weighing 16 lb. The fat on the loin in this breed, is to the lean as 5 or some- 

 times 6 to 1 ; and Mr. Marshall quotes an instance of an old New-Leicester sheep, 

 the quarter of which, weighing 261b. was reduced to 2|-lb. when divested of its 

 fat.* 



Farther ; the red colour of the internal parts of animals arises from the blood 

 which is contained in the vessels; and the redness of the blood itself depends on 

 the oxygen which it imbibes from the air, chiefly in the process of respiration- 

 Now exercise, by increasing the action ofihe heart, drives a larger quantity of blocd, 

 in a given time, through the lungs, and therefore accelerates respiration. The same 

 cause propels the blood more copic-usly through those minuter vessels, in which 

 otherwise it would either not exist, or else not be perceived by the naked eye. Hence 

 the blood, and all the parts through which it most circulates, are reddened by exer- 

 cise. We see this difference in individuals of the human race, who become pale and 

 sallow from indolence, but, from habitual exercise, obtain a clear carnation ; and 

 what is called the bloom of health. We see the difference in the common fowl, 

 which, when at large, and feeding at the barn-door, and in the fields, has dark- 



• Midland Counties, vol. i, page 399. 



