24 THL FOaM OF ANIMALS. 



The proper method of improving the form of animals, 

 consists in selecting a well-formed female, proportionally 

 larger than the male. The improvement depends on this 

 principle, that the power of the female to supply he' 

 offspring with nourishment is in proportion to her size, 

 and to the power of nourishing herself from the excel- 

 lence of her constitution. 



The size of the foetus is generally in proportion to that 

 of the male parent; and therefore, when the female pa- 

 rent is disproportionately small, the quantity of nourish- 

 ment is deficient, and her offspring has all the dispro- 

 portions of a starveling. But when the female, from her 

 size and good constitution, is more than adequate to the 

 nourishment of a foetus of a smaller male than herself, 

 the growth must be proportionately greater. The larger 

 female has also a greater quantity of milk, and her off- 

 spring is more abundantly supplied with nourishment 

 after birth. 



To produce the most perfect formed animal, aOundant 

 nourishment is necessary from the earliest period of its 

 existence, until its growth is complete. 



It has been observed, in the beginning of this paper, 

 that the power to prepare the greatest quantity of nour- 

 ishment, from a given quantity of food, depends princi- 

 pally upon 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 a large size, to be put 

 to a w^ell-formed male of a variety that is rather smaller. 



By such a method of crossing, the lungs and heart 

 become proportionately larger, in consequence of a pe- 

 culiarity in the circulation of the foetus, which causes a 

 larger proportion of the blood, under such circumstances, 

 10 be distributed to the lungs than to the other parts of 



