214 CROSSING AND CLOSE-INTERBREEDING. 



manifested in the general organization, and of all the 

 disorder in the reproductive system. The power of 

 propagation, in the parents, and the constitutional 

 vigor of the offspring, are lessened, in proportion to 

 the amount of departure from the sum of all the 

 characters; and are increased, in proportion as the 

 individuals return to that type. It is not relationship, 

 which causes the evil. Relationship simply implies 

 similarity of structure, in the parents. The evils of 

 lessened fertility, and of lessened constitutional vigor, 

 are displayed, when the parents are similarly dispro- 

 portionately developed, similarly wanting, or simi- 

 larly defective, in features of their species. 



The loss, or reduction, of any characters, is dele- 

 terious to either parent : When the parents pair, the 

 evil, consequent upon such loss or reduction, is aggra- 

 vated, or intensified. Thus, there are one hundred 

 and fifty different varieties of the pigeon. The mem- 

 bers of each divergent variety, necessarily lack the 

 positive peculiarities of the other varieties. If, then, 

 two of the same variety interbreed, the evil, entailed 

 by the absence of the positive peculiarities of the 

 other varieties, is intensified. 



Full health of the whole, or full functional activity 

 of the whole organism, subsists, not in the develop- 

 ment of some parts, or of some organs alone, but 

 solely in the full development of them all. Perfect 

 fertility, or perfect, constitutional vigor, consists only 

 with the sum of all the positive features of the species. 

 The capacity of the reproductive elements, is depend- 

 ent upon the full representation, therein, of all the 



