PO UL TR T- CRAFT. 



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that all variations except the small number coming in class 3, are due to 

 inheritance ; for it is a matter of common information that offspring do not 

 inherit equally from both parents ; that offspring of the same parents do not 

 inherit alike ; and that inheritance is not the transmittance of qualities from 

 one generation to the next in a lump, but goes back, " takes back " through 

 several of the nearest generations, and in less degree to more remote genera- 

 tions. Now if the law of inheritance accounts for likenesses, slight differences, 

 and a part of the greater differences, including some unusual, new, qualities, it 

 is to be expected that it can account for so-called " spontaneous " variations, 

 which are simply variations of which the causes are not immediately apparent. 

 Further, the law of inheritance requires that such phenomena of heredity as 

 these spontaneous variations shall occur from time to time, just as imperatively 

 as it requires that they shall take place only at long intervals. There is no 

 place in this work for an extended demonstration of this proposition. It can, 

 perhaps, be made sufficiently clear in a few words. 



Some observed facts of heredity, observations of the number of generations 

 required to establish, " breed in," a desirable trait, or to " breed out" an 

 undesirable one, give the general rule : A descendant inherits one-fourth of 

 the total of his qualities from each parent, one-sixteenth from each grand- 

 parent, one-sixty-fourth from each great-grand-parent, one-two hundred 

 and fifty-sixth from each great-great-grand parent. To put it another 

 way : an individual, a fowl, may inherit an appreciable fraction of its qualities 

 from each and every one of thirty ancestors, representing possibly the extremes 

 of divergence from the breed type in a dozen different respects. The number 

 of inheritable qualities is very great. The number of possible variations due 

 to inheritance is enormous, practically infinite. The mathematical rule based 

 on a few facts of inheritance teaches that slight variations should be very 

 numerous, considerable variations more rare, and that at long intervals 

 remarkable variations due to a fortuitous combination of two obsolete qualities, 

 or of known and obsolete qualities, should occur. And since the law of 

 inheritance, of the transmission of qualities, can explain the transmission of 

 unlike as well as of like qualities, it is neither sensible nor scientific to 

 attribute a few phenomena to some other mysterious cause. The breeders' 

 maxim, " Like begets like" is literally true, and applies to differences as well 

 as to resemblances. Every principle of breeding must conform to the law 

 of inheritance. Every phenomenon of reproduction can be explained in 

 accordance with the law, when all the the facts are known. 



195. What the Law of Inheritance Is, and What It Means to the 

 Poultry Breeder. The law of inheritance is a natural law; it simply 

 expresses the relation between descendant and ancestors. It does not, and 

 cannot show how heredity can be so controlled as to effect the direct trans- 

 mission of such particular qualities as the breeder esteems, and the immediate 

 suppression of all others. As this is precisely what the poultry breeder would 

 like to learn how to do, of what value is such a law to him ? Just this : the 



