300 SCIENCE OF AGRICULTURE. Part II. 



is the most frequent cause, they remain weak during life. Large bones, therefore, gwierally indicate an 

 imperfection in the organs of nutrition. 



2(X)4. To obtain the most improved form, the two modes of breeding described as the in- 

 and-in and crossing modes, have been practised. The first mode may be the better practice, 

 when a particular variety approaches perfection in form ; especially for those who may 

 not be acquainted with the principles on which improvement depends. When the male 

 is much larger than the female, the offspring is generally of an imperfect form. If the 

 female be proportionately larger than the male, the offspring is of an improved form. 

 For instance, if a well formed large ram be put to ewes proportionately smaller, the 

 iambs will not be so well shaped as their parents ; but if a small ram be put to larger 

 ewes, the lambs will be of an improved form. The proper method of improving the 

 form of animals consists in selecting a well formed female, proportionately larger than 

 the male. The improvement depends on this principle, that the power of the female to 

 supply her offspring with nourishment, is in proportion to her size, and to the power of 

 nourishing herself from the excellence of her constitution. The size of the foetus is 

 generally in proportion to that of the male parent ; and therefore, when the female parent 

 is disproportionately small, the quantity of nourishment is deficient, and her offspring 

 has all the disproportions of a starveling. But when the female, from her size and good 

 constitution, is more than adequate to the nourishment of a fcetus of a smaller male than 

 herself, the growth must be proportionately greater. The larger female has also a larger 

 quantity of milk, and her offspring is more abundantly supplied with nourishment after 

 birth. 



2005. Abundant nourishment is necessary to produce the most perfect formed animal, from the earliest 

 period of its existence until its growth is complete. As already observed, the power to prepare the greatest 

 quantity of nourishment from a given quantity of food, depends principally on the magnitude of the lungs, 

 to which the organs of digestion are subservient. To obtain animals with large lungs, crossing is the most 

 expeditious method ; because well formed females may be selected from a variety of large size, to be put 

 to a well formed male of a variety ; that is, rather smaller. By such a mode of crossing, the lungs and 

 heart become proportionately larger, in consequence of a peculiarity in the circulation of the foetus, which 

 causes a larger proportion of the blood, under such circumstances, to be distributed to the lungs than to 

 the other parts of the body ; and as the shape and size of the chest depend upon that of the lungs, hence 

 arises that remarkably large chest, which is produced by crossing with females that are larger than the 

 males. The practice, according to this principle of imi)rovemeiit, however, ought to be limited ; for it 

 may be carried to such an extent, that the bulk of the body might be so disproportioned to the size of the 

 limbs as to prevent the animal from moving with sufficient facility. In animals, where activity is required, 

 this practice should not be extended so far as in those which are intended for the food of man. 



2006. The characters of animals, or the external appearances by which the varieties of 

 the same species are distinguished, are observed in the offspring ; but those of the male parent 

 more frequently predominate. Thus in the breeding of horned animals there are many 

 varieties of sheep, and some of cattle, which are hornless. If a hornless ram be put to 

 horned ewes, almost all the lambs will be hornless ; partaking of the character of the 

 male more than of the female parent. In some countries, as Norfolk, Wiltshire, and 

 Dorsetshire, most of the sheep have horns. In Norfolk the horns may be got rid of, by 

 crossing with Ryeland rams ; which would also improve the form of the chest, and the 

 quality of wool. In Wiltshire and Dorsetshire, the same improvements might be made, 

 by crossing the sheep with South Down rams. An offspring without horns, or rarely 

 producing horns, might be obtained from the Devonshire cattle, by crossing with horn- 

 less bulls of the Galloway breed; which would also improve the form of the chest j in 

 which the Devonshire cattle are often deficient. 



2007. Examples of the good effects of crossing may be found in the improved breeds of horses and 

 swine in England. The great improvement of the breed of horses arose trom crossing with the dimi- 

 nutive stallions. Barbs and Arabians ; and the introduction of Flanders mares into this country was the 

 source of improvement in the breed of cart horses. The form of the swine has been greatly improved, by 

 crossing with the small Chinese boar. 



2008. Examples of the bad effects of crossing 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 legged, 

 large boned, worthless 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 to the shape of the carcase, 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. 



2009. 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 which they inhabit. Where produce is nutri- 

 tive and abundant, the animals are large, having grown proportionally to the quantity of 

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



