CROSSING AND CLOSE-INTERBREEDING. 21 T 



proportionate development of all the characters of 

 their species, the evil will, either, be less, from the- 

 intermarriage of brother and sister; or, be the same, if 

 the interbreeding be carried on for more than one gen- 

 eration. If the approach to the original type of the 

 species be nearer, the interbreeding of brother and 

 sister, may be carried on, for many generations; but, 

 the effects of the slight disproportionate development, 

 will begin to tell, after some period of such long-con- 

 tinued close-interbreeding. 



If there be no reduction or suppression of any of 

 the characters of the species, and no disproportionate 

 development whatsoever, the original type is then 

 realized, and interbreeding may be carried on, ad in- 

 finitum, in any degree of relationship, however close, 

 without any evil effects; provided, of course, the in- 

 dividuals, in question, always retain their full integrity, 

 and, that each of those individuals with which any 

 such interbreeds, is alike the sum of all the positive 

 features of the species. 



The above descending scale of effects obtains, of 

 course, only where the law of inheritance fully oper- 

 ates, where like produces like, and where relationship 

 actually occasions, what it generally implies, viz., simi- 

 larity of defects. The effect is .due, to each parent 

 lacking like points of structure, and to the aggra- 

 vation, or augmentation of such evil, in the off- 

 spring. 



The evils, from close-interbreeding, grow less and 

 less as the integrity of the organism is repaired or 

 regained; or, they grow greater and greater, in pro- 

 19* 



