108 PEmCIPLES AND PKACTICE OF BKEEDINO. 



the same halves, in the same order, both with respect to form 

 and general properties.* 



According to Mr. Walker the effects of crossing, among 

 animals of different breeds, would generally absolutely stop and 

 become unchangeable with the first cross, for every generation 

 of descendants would receive the same half of the organization 

 without any modification 1 And on the other hand, between 

 animals of the same breed, the descendants might either 

 permanently exhibit the same relative paternal and maternal 

 halves, or they might by in-and-in breeding, in the second 

 generation, become exactly like their sire in both halves I f 



The theory of propagation by halves appears to have 

 considerable support from facts when it is applied to hybrids — 

 animals derived from inter-brecding distinct species, — as for 

 instance the male ass with the mare, the horse with the female 

 ass, the goat with the sheep, etc. But as applied to sheep, 

 every observing breeder ought to know that it is essentially 

 unfounded and chimerical. The Merino ram crossed with a 

 ewe of some thin and coarse-wooled family, does not, either 

 fully or approximately, transmit the weight, fineness or other 



* If this were so, half bloods, when bred tpgcther, would jeprodnce their own 

 essential qualities about as uniformly as full bloods when bred together; and the 

 attempt to form them into permanent families, occupying the same relative place they 

 do between the original breeds of which they are comi)osed, should result in as splendid 

 success as it does, in point of fact, in complete and uniform failure. And by this theory, 

 it would seem the half blood ram ought always to be used to perpetuate half bloods — 

 yet experience shows that half blood rams are worthless for that object. I never have 

 seen anything more than extracts from Mr. Orton's paper on this subject. I do not 

 therefore know what exceptions he made for breeding back. He must of course have 

 regarded it as only the exception, or else he could not have assumed any set of facts 

 opposed to it to be the rule. Then, in his view, a msOority at least of the descendants 

 of half bloods, bred to half bloods, or to mongrels of their own degree, would 

 continue uniformly to produce their own essential characteristics, — which every 

 observing breeder knows they do not do. 



t Mr. Walker says : — "Let the example be that in which, of the animals subjected 

 to in-and-in breeding, the father breeds with the daughter, and again with the grand- 

 daughter. Now, it Is certain the father gives half his organization to the daughter, 

 (suppose the anterior series of organs,) and so far th6y are identical; but, in breeding 

 with the daughter, he may give the other half of his organization to the grand-daughter, 

 (namely, the posterior series of organs,) andas the grand-daughter will then have both 

 his series of organs — the former irom the mother and the latter from himself — it is 

 evident that there exists between the male and his grand-daughter a quasi identity, 

 [p. 210 J 



Mr. Spooner does not develop his views very fully, but so far as he states them, 

 he would appear to adopt Mr. Walker's theory of a strict propagation by halves, and at 

 the same time to assume, by implication, that either parent may give either series of 

 organs, in all cases, as Mr. Walker only assumes they may among animals of the same 

 breed. If these are Mr. Spooner's real opinions, he must be prepared to believe that 

 results like the following may ensue : — K a Merino ram was put to a Leicester ewe he 

 would transmit half of nis organization to their common progeny. If the same ram 

 was put to his own half-blood daughter of that cross, he might give the other half of 

 his organization to the progeny, so that it would be, de facto^ a pure Merino. This 

 would be a very summary process of creating pure M.erinos out of Leicesters 1 If the 

 same rule held good in regard to horses, an Arabian stallion might in two generations 

 produce pure Arabian stock from cart mares 1 Is Mr. Spooner prepared to adopt such 

 a sequitur to his theory ? 



