216 CROSSING AND CLOSE-INTERBREEDING. 



proportionate development of the individuals, — will 

 the individuals, when interbred, dwindle, grow feeble, 

 become of lessened fertility, and eventually grow 

 sterile. 



If a great number of characters, of the respective 

 species, be reduced, or suppressed, the evil will ensue 

 immediately, with any individual bred with another of 

 the same variety ; although there subsist between the 

 two, no degree of relationship. If the number of 

 characters so lost or reduced, be a degree less, the 

 evil will, either, be less, from the same degree of in- 

 terbreeding ; or be the same, from interbreeding with 

 a distant relative. If, still less, be the loss or reduc- 

 tion, the evil will, either, be less from the last men- 

 tioned degree of interbreeding; or, be the same, from 

 interbreeding with a relative, a degree nearer. If, 

 less, again, be the disproportionate development, the 

 evil will, either, be less, in the last named degree of 

 relationship; or, be the same, only, with a nearer rela- 

 tive (say), a cousin. If, less, still, the evil will, either, 

 be less, with the cousin; or, be the same, if the inter- 

 breeding, with a cousin, be continued for more than 

 one generation ; or, be the same, from an intermar- 

 riage of father and daughter, or of mother and son. 

 If the reduction, or suppression, of characters, be 

 small, the evil will, either, be less from the inter- 

 breeding of a son and mother, or of a father and 

 daughter ; or, be the same, if such interbreeding be 

 continued for more than one generation ; or, be the 

 same, if the intermarriage be between brother and 

 sister. If the organisms approximate the full and' 



