BREEDS AND THE PRINCIPLES OF BREEDING. 413 



of animals and plants. The commonly recognized law of heredity is, that &quot;like produces 

 like,&quot; and this must hold true to a great extent, or the existence of breeds would be an 

 impossibility; but if it were absolutely true, or it were an arbitrary rule which nature strictly 

 enforced in every particular, it is evident that neither by man s interference nor the operations 

 of nature could a new breed or race be produced, since the offspring would in all cases be 

 identical with the parents. It seems, therefore, that owing to the exceptions to this general 

 rule or law of nature, which renders it possible for difference in conditions and circumstances 

 to produce different results, new breeds have arisen. 



In plants, a new variety of species is produced by crossing one variety on another. In 

 crossing two different species of a genus, a hybrid is produced, the fertility of which is gen- 

 erally destroyed, hence the hybrid rarely perpetuates its kind. Prof. D. C. Eaton, of Yale 

 College, says respecting hybrids: 



&quot; It may therefore be said of hybrids generally, that they are either sterile, or, if fertile, 

 that they will most frequently return, after a few generations, to their parent forms. 



Hybrids can be produced only between nearly related forms. So true is this law believed 

 to be, that Darwin seems to suspect the inaccuracy of any zoological classification which 

 places in different genera animals between which hybridity is possible. Every story of a 

 monster, half one thing and half something utterly different, no matter how high the authority 

 for the story, is necessarily and absolutely false, and such fabled creatures must be relegated 

 to the category of the minotaur, the centaur, and that product of the Mississippi valley, 

 which is said to be half alligator and half horse. Dogs cross freely with wolves and jack 

 als, because these are all very closely related, but between dogs and all animals other than 

 canidce, or dog-like creatures, there is no possibility of hybridism. 



So also in the vegetable kingdom: there is no hybridizing of unrelated plants. The apple 

 and the wild American crab-apple have been hybridized, and I believe, with the result of 

 producing a valuable fruit; but any attempt to hybridize the apple and the peach, or the 

 plum and the pomegranate would be utterly vain. Various kinds of grapes have been 

 hybridized with most valuable results. Very many kinds of cultivated strawberries are the 

 outcome of successful hybridizing, and it is probable that a good many of our fruits have 

 in them the strains of more than one original species. But it should be remembered that 

 these kinds of grapes, strawberries, plums, gooseberries, etc., are not permanent varieties, 

 using the word in its proper sense; they are only hybrid or mongrel productions, with 

 individual peculiarities, but multiplied by division of the root stocks, by runners, by 

 grafting, by budding, by slips. None of them could be depended on to reproduce itself by 

 seed, and if the seed should grow at all, which is not always certain, the offspring would in 

 all probability show strong tendencies to revert to one or both of the original parent forms.&quot; 



&quot;When two animals or plants of the same species are crossed, but differing one from the 

 other, the product will be fertile, though not in so great a degree as in those of a like kind. 



In such cases the offspring will resemble one parent more strongly than another, and 

 these varieties will be very liable to reappear in after generations. This reversion to remote 

 ancestry, commonly termed atavism, is seen in many breeds, notwithstanding the care taken 

 in breeding, and the many years passed after the particular cross was made. 



Prof. W. H. Brewer, of Yale College, says in regard to forming new varieties of plants, 

 &quot; Suppose that suddenly, by a miracle, every kind of cultivated apples in the world were 

 swept out of existence, and we were left with only the original wild stock to begin anew 

 with, but had all our present knowledge bearing on the question of again recovering the lost 

 treasure. How should we go to work; what methods and means has science and art to sug 

 gest, whereby to transmute that small, sour, acrid, puckery crab-apple into the luscious and 

 various kinds of apples we had lost, and change the crabbed, thorny shrub of the hedges 

 into the comely, thornless tree of the orchards ? 



