The last forty years of scientific progress has established firmly the general theories of Darwin, but they have also resulted in our questioning his idea that all great changes are due to the sum of small variations.  Many instances have been suggested in which the theory of gradual changes could not explain the facts.

The theory of mutation, of which Hugo de Vries, of Holland, is the chief expounder, does not antagonize Darwin, but simply gives more weight in the process of evolution to the factor of sudden changes commonly called sports.  Let us illustrate:  In the giraffe of our former forest, one might appear whose neck was not longer because of slightly longer vertebrae, but who possessed an extra vertebrae.  This would be a mutation.  In other words, a mutation is a marked variation that may be inherited.  We now believe that polled cattle, five-toed Dorkings, top-knotted Houdans, frizzles and black skinned chickens arose through mutations.

Burbank’s Methods—­The wonderful Burbank with his thornless cactus, his stoneless plum, and his white blackberry, is simply a searcher after mutations.  His success is not because he uses any secret methods, but because of the size of his operations.  He produces his specimens by the millions, and in these millions looks, and often looks in vain for the lonely sport that is to father a new race.  Burbank has, with plants, many advantages of which the animal breeder is deprived.  He can produce his specimens in greater number, he can more easily find out the desirable character, and in many plants he has not the uncertain element of double parentage to contend with, while with others he is still more fortunate, as he can produce them by seed, stimulate variation until the desired mutation is found and can then reproduce the desired variation with certainty by the use of cuttings.  This latter is not true inheritance with its inevitable variation, but the indefinite prolongation of the life of one individual.  In this sense there is only one seedless orange tree in the world.

The Centgenitor System—­Prof.  Hays in breeding wheat at Minnesota, first used in this country a system of breeding which is essentially as follows:  A large variety of individual seeds are selected.  These are planted separately and the amount and character of the yield observed.  The offspring of one seed is kept separate for several generations, or until the character of the tribe is thoroughly established.  The advantage of this plan of breeding is in that the selection is not made by comparing individuals, but by comparing the offspring of individuals.  Thus, we necessarily select the only trait really worth while; that is prepotency or the ability to beget desirable qualities.

The application of this centgenitor system necessitates inbreeding; it also necessitates large operations.  Of the former, breeders have generally been afraid; of the latter they have lacked opportunity.  But the centgenitor system, combined with Burbank’s principle of large opportunity of selection, is, in the writer’s belief, the method by which the 200-egg hen will be ultimately established in America.