88 BOARD OF AGRICULTURE. 



In applying this law of inheritance there are several consid- 

 erations to be taken into account. First : If there is a great 

 similarity of organization in the parent stock, — an even bal- 

 ance of organs on both sides, — there will be a resemblance in 

 the progeny, though generally an improvement, and seldom 

 any marked excesses or defects. When this course of breed- 

 ing is followed, it takes a long time to bring about marked 

 changes, either for better or worse. But as there are many 

 secondar}' causes, both internal and external, operating to 

 change the development of certain organs of the body, it 

 becomes veiy difficult to perpetuate this standard through 

 successive ireueratious. Then we should add to these causes 

 the agency of disease, M'hich may seize the most perfectly or- 

 •ganized animal, when its symptoms, which lurk unnoticed in 

 the system, are not visible at the time, and when its effects 

 are slight at first, but b}' transmission from generation to gen- 

 eration o;row into most serious evils. 



BREEDING " EST AND IN." 



There is one mode of improving stock which can be explained 

 b}^ this law of propagation in a most satisfactory manner ; in 

 foct, can be explained in no other wa3^ "We refer to the prac- 

 tice of what is called breeding " in and in," which has had 

 both its advocates and opponents. This practice has b}' some 

 been attended with great success, and by others with equally 

 as marked failures. There certainly must be some things or 

 conditions in it favorable, while, on the other hand, there are 

 some imfavorable. Xow, what are these, and what is' the 

 explanation ? It surely cannot be in the blood or mere rela- 

 tionship alone, for the chemical qualities of the blood may be 

 precisely the same in all, and whether it courses in larger or 

 smaller quantities within the kindred circle, this difference 

 cannot produce such marked results. The same principle 

 applies to the human species in what is called the " intermar- 

 riage of relations." The evil consequences here are not more 

 marked. It has been found, by a long series of facts, that the 

 nearer the relationship the worse have been the results, and 

 that in the second, third and fourth degrees of kindred the evil 

 results have sfrown less and less. The o^reat secret is, that in 

 this close relationship there is found an organization too much 



