THE CROSSING, AC, OF CATTLE, ET At. 309 



economizes facts which are " ugly'' in the aspect they 

 wear towards his theory, should have adduced these 

 phenomena, respecting Cattle and Sheep, which mili- 

 tate so strongly against his "law." 



There is one explanation, which needs not any con- 

 jecture, to establish its soundness. It is, — that he is bent 

 upon showing, that the whole subject of fertility is so 

 completely "muddled," that it is unfair to draw any 

 inference, against his theory, from the sterility of hy- 

 brids. As before intimated, it shall be demonstrated 

 how little such an ingenious device avails him. An- 

 other reason, which may explain why he adduces the 

 evidence of the exemption, of these proportionately 

 developed animals, from the evils of^ interbreeding, is, 

 that he doubtless deems the strength and validity of 

 his " law," in question and in doubt, until he shows 

 exceptions to its operation; — upon the principle, that 

 "the exceptions prove the rule." If such be the case, 

 his readers have a perfect Bonanza of assurance upon 

 that point. 



On page 175, Vol. ii, Animals and Plants, &c, 

 he again reiterates his "great law of nature," and 

 adds : 



"The rule applies to all animals, even to Cattle and 

 Sheep, which can long resist breeding in-and-in 

 between the nearest blood relations." 



The fact, of his here being necessitated to note, that 

 the rule applies " even to Cattle and Sheep," is not 

 without its significance. 



Again he says (p. 213, Vol, ii, Animals and Plants, 



&c), referring to Cattle and Sheep, and, doubtless, to 

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