76 PRINCIPLES OF STOCK-BREEDING. 



to a remote ancestor, that differs in many respects 

 from the parents, cannot be referred to a " spon- 

 taneous variation " in the law of inheritance, for we 

 cannot conceive of an effect without an efficient 

 cause. 



The repetition of some preexisting character is so 

 uniformly observed in all cases of apparent variation 

 in the transmission of qualities, in which the history 

 of the ancestors can be traced, that we cannot avoid 

 the conclusion that these peculiarities in the heredity 

 of the organization are the result of some constant 

 and definite physiological law. 



If the form in which the physiological units or 

 elements of the organization were transmitted could 

 be determined, the obscurity involved in this class of 

 cases would in great measure disappear. 



' In discussing 'the subject of inherited resemblance, 

 Dr. Carpenter remarks that "the question seems to 

 have been entirely ignored, whether the union of two 

 different natures may not produce as in the combi- 

 nation of an acid and a base a resultant essentially 

 dissimilar to either of them." 1 



If two characters may thus blend to form a new 

 character essentially different, there could be no con- 

 stancy in the transmission of ancestral forms from 

 generation to generation, and a wide variation from 

 the family type would necessarily result. There could 

 be no uniformity in the leading characteristics of our 

 improved breeds, and, with our present knowledge of 

 physiological science, the breeding of animals would 

 be attended with the greatest uncertainty, from our 



1 "Mental Physiology," p. 369. 



