This retarded development has no doubt been largely due to the fact that biology requires all the other sciences as its servants, and it is only as chemistry and botany and physics and geology have progressed that the biologist has been able to find satisfactory data and material for his attempts to reveal the nature and origin of the various forms of life.
It is true that Darwin studied very closely the work of British stock breeders and referred largely to their work in his subsequent writings to explain and illustrate his theory of the origin of species through natural selection. The principal part of the constructive work of British stock breeders, however, had been done in the first half of last century, and the indebtedness of stock breeding to Darwin was by no means so considerable as the service that industry afforded to the naturalists of the time and to Darwin in particular.
It was not until 1859 that the "Origin of Species" was printed. Remembering, then, the revolutionizing aspect of the first reasonable explanations of the development of the forms of life, and the difficulties opposed to the general acceptance of natural selection as the main evolutionary factor, it is not very surprising that the economic value of such truth has received scant attention.
To interpret a science to an industry requires some individuals interested and qualified in both fields. If botany and zoology, in former years, attracted any men really conversant with agriculture, their full endowments have been devoted to some of the numerous engrossing and fascinating questions of pure science. So we find that until ten years ago it could scarcely be said that any scientific students of heredity were seriously attempting to serve agriculture.
The men who had done so much in the molding of animal form could not be called scientific; complete strangers to any conception of the physical basis of heredity they worked solely as directed by their own experience and such meager teachings as were obtainable from their predecessors. What little constructive work had been accomplished in the plant kingdom was effected by self-taught men of unusual natural endowments for the work.
It would be a serious mistake to lose sight of the fact that wonderful improvements had been effected by development and improvement of numerous varieties of both plants and animals long before any physiological explanation of heredity was attempted. It is quite clear, however, that the principles underlying the achievements of those earlier self-taught master breeders were very imperfectly understood as principles; indeed, it did not seem to them that a satisfactory explanation of their experiences could ever be forthcoming. Breeding was not an art based upon science, but was purely an artistic calling. This being true, it has been impossible to prepare younger men to