Maternal Organs of Reproduction in Animals. 



249 



danger. Essential therefore to success is a knowledge of the 

 principles to which we have alluded, and which will form the 

 basis of this discourse. 



It is not our intention to enter on the vexed question of the 

 best means to improve the breed of any particular class of 

 animals, nevertheless we may be allowed to make a few passing 

 remarks on what is commonly designated " the theory and practice 

 of breeding." 



Breeding with a view to improvement may be said to be founded 

 on an established law of nature, that like produces like. We 

 should, however, always bear in mind that in animals there is a 

 perpetual tendency to change, by which the development of their 

 frame and strength of constitution are materially influenced, 

 arising from a variety of causes, such as domestication, system of 

 management, removal to a different climate, a continued habitation 

 of the same district, partaking in general of the same diet, feeding 

 on many kinds of provender, a liberal or niggardly allowance of 

 food, especially when young, with protection from or exposure to 

 the inclemencies of the w T eather, &c. But although these may be 

 regarded as the chief causes in operation to produce the tendency 

 to change, still among them we have the required means to pro- 

 mote the permanent improvement of a breed. Thus it will be 

 seen that, in the language of Sir J. Sebright, et it is not always by 

 putting the best male to the best female that the best produce 

 will be obtained ; for should they both have a tendency to the 

 same defect, although in ever so slight a degree, it will in general 

 preponderate so much in the produce as to render it of little 

 value." * 



In order to improve a particular race of animals, two plans are 

 advocated by the two classes of practical breeders. One of these 

 is commonly called " the crossing," the other "the in-and-in" 

 system. The latter of these was strongly advocated by the late 

 Mr. Bakewell, and his example had at least the effect of destroying 

 the great prejudice which existed against breeding from animals 

 having a close relationship to each other. The too rigid adoption 

 of this plan is found, however, to produce degeneration, and there- 

 fore its advantages are limited: for animals of the same family, 

 living in the same locality, and subjected to the same system of 

 management, are predisposed to the same defects and diseases, 

 and these become hereditary. Besides which, every improvement 

 of a breed requires the application of the same means to maintain 

 it which produced it, and the chief of these is care in the selection 

 of both the male and female, so as to avoid the consequences of 

 that predisposition to which we have alluded. As with defects 

 so it is with improvements ; these are transmitted from parent to 



* " The Art of Improving the Breeds of Domestic Animals," by Sir John 

 Saunders Sebright, Bart., M.P, Londcu 1809. 



