196 CROSSING AND CLOSE-INTERBREEDING. 



the characters, of its species, is modified or absent. 

 They show, that the further that degeneration, under 

 nature, or that degeneration under domestication, has 

 been carried, the more is the physiological integrity of 

 the individuals, in question, impaired, on account of 

 the loss, in such individuals, of characters of their 

 respective species, or on account of the establishment of 

 an abnormal ratio of the characters of their respective 

 species. They show, that the further that positive 

 Reversion is carried, or the more that characters are 

 regained, and the nearer the original, perfect type of 

 the given species, is approximated, the greater is the 

 repair of this lost, physiological integrity. They show, 

 that, only when reversion has been fully effected, — 

 when all of the lost characters, of the respective 

 species, have been regained, — and when the sum of 

 all the positive features, of the given species, is realized 

 in the individual, can there be full, physiological per- 

 fection. 



The state of the individuals which vary, is shown to 

 be a deficient, physiological condition, previous to their 

 development of positive variations. That this is due , 

 to their then, deficient, structural condition, is attested 

 by the circumstance that in proportion as they return 

 to their full structural integrity, — that is, in proportion 

 as they vary positively, or re-develop the characters as- 

 sumed to have been originally lost, — do the physiologi- 

 cal evils abate, and cease altogether when the full 

 amount of positive variation possible for that species, 

 has been effected. The connection of the evil effects 

 with the deficient, structural condition of the indi- 



