Page:Popular Science Monthly Volume 78.djvu/557

Rh —rendering their work more intelligent and more scientific and consequently much more valuable. It has also drawn the attention of scientific workers to economic questions, and encouraged research, planned with some thought for economic interests and yet highly scientific.

Animal breeding has been influenced by Mendelism, chiefly through indirect means. The practical obstacles to rearing of large numbers of animals for the chance of finding some new thing has compelled animal breeders to go at a much slower pace than that set by the plant breeders. The fact that some characters of minor practical value have been shown to be inherited in definite proportions has stimulated an interest and study in other aspects of heredity that explains otherwise mysterious occurrences and dissipates common unscientific ideas that have done much to hinder real progress. Ten years ago when the possibilities of breeding up our farm crops were becoming apparent the accomplishments of breeders of animals were the incentive and patterns for those working with plants. To-day the situation is reversed, and work with plants is seen to be beset with fewer practical difficulties and productive of much earlier returns than equally skillful work in the animal kingdom.

Breeders and biologists are still far from unanimous in their opinions of the relation of environment to heredity. This fact is no serious hindrance to the breeder's work, however, except in so far as the heat and confusion which is the main product of discussions of the actual role of environment, require energy that could be more profitably utilized in some other way. Although a settlement of the question might permit a clearer conception of heredity and facilitate scientific inquiry, it could call for no considerable change in breeding practise. The majority of animal breeders firmly believe that the effects of environment are transmitted. Mr. Burbank also believes the same of plants; but neither Mr. Burbank nor any animal breeder has attempted a physiological explanation of such claimed occurrences. It is immaterial whether we emphasize environment or selection as the chief factor in the production and maintenance of variations. Both are essential, and to consider the changes in our domestic animals to be the outcome of artificial selection, aided and facilitated by adjusted environments, is quite as satisfying from the breeder's standpoint as ascribing first place to environment. Reliance upon selection, however, has the present advantage of being more nearly explained physiologically than is the other view.

Breeders of to-day, especially plant breeders, recognize more clearly