304 SCIENCE OF AGRICULTURE. Part II. 



source of improvement in the br ed of cart-horses. The form of the swine has been greatly improved by 

 crossing with the small Chinese boar. 



2()5i. Examples of the bad effects ofa-ossing the breed are more numerous. When it became the fashion 

 in London to drive large bay horses, the farmers in Yorkshire put their mares to much larger stallions 

 than usual, and thus did infinite mischief to their breed, by producing a race of small-chested, long-logged, 

 large-boned, wortliless animals. A similar project was adopted in Normandy, to enlarge the breed of 

 horses there, by the use of stallions from Holstein ; and, in consequence, the best breed of horses in France 

 would have been spoiled had not the farmers discovered their mistake in time, by observing the offspring 

 much inferior in form to that of the native stallions. Some graziers in the Isle of Sheppy conceived that 

 they could improve their sheep by large Lincolnshire rams ; the produce of which, however, was much 

 inferior in theshape of the carcass, and the quality of the wool ; and the flocks were greatly impaired by this 

 attempt to improve them. Attempts to improve the animals of a country by any plan of crossing should 

 be made with the greatest caution ; for by a mistaken practice, extensively pursued, irreparable mischief 

 may be done. In any country where a particular race of animals has continued for centuries, it may be 

 presumed that their constitution is adapted to the food and climate. 



2055. The pliancy of the animal economy is such, that an animal will gradually 

 accommodate itself to great vicissitudes in climate, and alterations in food ; and by de- 

 grees undergo great changes in constitution ; but these changes can be effected only by 

 degrees, and may often require a great number of successive generations for their accom- 

 plishment. It may be proper to improve the form of a native race, but at the same time 

 it may be very injudicious to attempt to enlarge their size ; for the size of animals is 

 commonly adapted to the soil and climate w^hich they inhabit. Where produce is nutri- 

 tive and abundant, the animals are largo, having grown proportionately to the quantity of 

 food which, for generations, they have been accustomed to obtain. Where the produce is 

 scanty, the animals are small, being proportioned to the quantity of food which they were 

 able to procure. Of these contrasts the sheep of Lincolnshire and of Wales are examples. 

 The sheep of Lincolnshire would starve on the mountains of Wales. 



2056. Crossing the breed of animals may be attended ivith bad effects in various ways, 

 and that even when adopted in the beginning on a good principle. For instance, suppose 

 some larger ewes than those of the native breed were taken to the mountains of Wales, 

 and put to the rams of that country, if these foreign ewes were fed in proportion to their 

 size, their lambs would be of an improved form, and larger in size than the native 

 animals ; but the males produced by this cross, though of a good form, would be dispro- 

 portionate in size to the native ewes ; and, therefore, if permitted to mix with them, 

 would be productive of a starveling, ill-formed progeny. Thus a cross, which at first 

 was an improvement, would, by giving occasion to a contrary cross, ultimately prejudice 

 the breed. The general mistake in crossing has arisen from an attempt to increase the 

 size of a native race of animals ; being a fruitless effort to counteract the laws of nature. 

 No attempt to enlarge the size of animals by any mode of breeding will ever succeed 

 without a corresponding change in the quantity and quality of their food, and their 

 means of procuring it without much fatigue. The climate also requires attention. An 

 improved short horn could never arrive at perfection on the scanty and coarse fare, and 

 severe climate, of the Highlands of Scotland. Size, in fact, is a very subordinate con- 

 sideration. The great object, as observed above ( 2021.), is to obtain the greatest 

 possible return for the food consumed ; and it is only where both the quantity and 

 quality are in great abundance, that large animals, if of a good description, may be 

 preferred to small ones. 



2057. The Arabian horses are, in general, the most perfect in the world; which 

 probably has arisen from great care in selection, and also from being unmixed with any 

 variety of the same species ; the males, therefore, have never been disproportioned in size 

 to the females. 



2058. The native horses of India are small, but well proportioned, and good of their 

 kind. With the intention of increasing their size, the India company have adopted a 

 plan of sending large stallions to India. If these stallions should be extensively used, 

 a disproportioned race must be the result, and a valuable breed of horses may be 

 irretrievably spoiled. 



2059. From theory, from practice, and from extensive observation, the last more to be 

 depended on than either, " it is reasonable," Cline continues, " to form this conclusion : 

 it is wrong to enlarge a native breed of animals, for in proportion to their increase of size, 

 they become worse in form, less hardy, and more liable to disease." {Communications to 

 the B. ofJg., vol. iv. p. 446.) 



2060. The above opinions may be considered as supported by the most eminent 

 practical breeders, as Bakewell, CuUey, Somerville, Parry, and others ; and by most 

 theorists, as Coventry, Darwin, Hunt, Young, &c. T. A. Knight writes in the Com- 

 munications to the Board of Agriculture in favour of cross-breeding, as do Pitt and others 

 in the County Surveys, but mostly from very limited experience. Sir J. S. Sebright, in 

 a letter addressed to Sir Joseph Banks, on improving the breed of domestic animals, 1809, 

 has taken the opposite side of the question ; but the meaning he attaches to the term 

 breeding in-and-in is so limited, as to render it a very different sort of breeding from that 

 practised by Messrs. Bakewell and Culley, which has been generally so named and recom- 

 mended by Cline and others, who favour, rather than otherwise, the in-and-in system. 



