276 THE CROSSING, 4C, OF PIGEONS AND FOWLS. 



which have the development of one character alone 

 carried to an extreme point, be saved from extinction. 

 The following is the cycle, around which such abnormal 

 types must swing : They diverge, in character; meet, 

 in consequence, the plainest threat of absolute sterility 

 and death from interbreeding'; they then forsake their 

 types, for the nonce, .to retrieve, by crossing, the char- 

 acters they need, to secure physiological repair; and 

 then diverge, anew, to repeat again the same round. 



Such a round, however, has not long been pursued, 

 in the past. These divergent varieties have died out, 

 from the evil effects which such an abnormal ratio of 

 development of their characters has entailed. The 

 seeming, long continuance of high fancy breeds of 

 Pigeons, for instance, is due, not to those breeds hav- 

 ing perpetuated their kind, for such length of time; 

 but, to such breeds, having been recruited, from time 

 to time, by accessions from the wild pigeon stock 

 which, though degenerate, is yet of greater physiologi- 

 cal value, owing to the proportion of the characters 

 being better preserved, than it is in those breeds 

 wherein one or more characters are given an undue k 

 ascendancy. It is impossible for any breed or variety, 

 long to exist and preserve its type, when it lacks many 

 of the characters of its species. Forms, and groups of 

 forms, have disappeared from the earth. These forms, 

 after having arisen, have spread and continued abund- 

 ant for an era, and have eventually declined and 

 become extinct. It is not necessary, to invoke cata- 

 clysms, with which to account for species having been 

 swept from the face of the earth. Certain sets of con- 



