THE orchard, the vegetable garden and the ornamental garden are old institutions, and many of the practices and traditions of them are nearly everywhere familiar. Collectively they constitute horticulture, and horticulture, like agriculture, is known as the oldest of arts. But horticulture is an art which rests immediately upon a science, and singularly enough, this science is to this day almost wholly unrecognized as one separate and peculiar. Science in its direct application to agriculture in general is among the latest forms of knowledge and practice, and its application to horticulture in particular is almost the latest of the latest. If it is strange that such is the case, there is nevertheless a reason for it. This science is largely a knowledge of plants ; yet botany, of right the science of plants, has fixed for itself a wholly conventional boundary, and has not reached the garden. It pursues the study of plants whose parts and habits are normal, or natural, as some would say, which have never been modified by the agency of man. Botany has been repelled by the garden fence, and has failed to reap its own best fruits.

The difficulties of studies in the garden have discouraged botanists. "Roses have ceased to be a botanical study," our most eminent botanist once said to the writer. There is also a feeling among botanists that cultivated plants are scarcely worth the trouble of study. "How can you be a horticulturist ? How can you love the garden ?" a botanist of note once enquired of me. So the scientific study of garden plants has been neglected largely because the science to which it belongs has not claimed it.

It needs no argument to convince the reader that cultivated plants form an inestimable part of the possessions of the race. Darwin declared that "one new variety raised by man will be a more important and interesting subject for study than one more species added to the infinitude of already recorded species." That this addition, origination, of new varieties has been almost wholly haphazard, is no excuse for its neglect. There is no chance in nature, and somehow, sometime, we shall find out how and why it is that a peach can give birth to a nectarine or a white flower can produce a red flower. Or, of truth, we must first determine why a peach can give birth to a peach, or a white flower can produce a white flower. In other words, we must determine why and how it is that plants possess hered ity, and vary, and can be made to vary under culture. We must come to a practical understanding of the fact that pedigree means as much in plants as in animals.

We shall look for the operation of the same laws in the garden as in the fields and woods, with the addition of the modification and intensification wrought by artificial conditions. The horticulturist begins where the botanist leaves off: he steps beyond the action of purely natural forces into the larger inquiry of natural forces as modified by man. It was the study of domesticated plants and animals that led Darwin to discern Darwinism. He was first struck by great likenesses of species when in the Galapagos archipelago: "But it long remained to me an inexplicable problem how the necessary degree of modification could have been effected, and it would thus have remained forever had I not studied domestic productions, and thus acquired a just idea of the power of selection".

In essence, man's cultivation is the same as nature's. Cultivation means, chiefly, an increase in food supply for the plant. If the cultivator adds food in fertilizers, so does nature, and nature's practice is far the more perfect. If man gives the plant space in which to grow, so does nature by thinning out the weakest in the inevitable crowding of individuals, or again through the law of divergence of character, by virtue of which more plants of many kinds can be grown upon a given area than of one kind. If man tills, so does nature, by the annual mulch of herbage. If man prunes, so does nature, by training and trimming the stem of the sapling into the bole of the tree, and by suppressing ten buds to every one that grows. Cultivation is but an empiricism suggested by nature. *' Man, therefore," says Darwin, "may be said to have been trying an experiment on a gigantic scale; and it is an experiment which nature during the long lapse of time has incessantly tried".

As man's efforts are intenser than nature's, so his labors have given more marked results; or, to speak precisely, nature has yielded to his efforts. Animals and plants have varied so widely from their aboriginal ancestors, in many cases, as to be unrecognizable as individuals of the same species; and yet there is every reason to believe that variation of far greater extent and importance is possible. In plants, the study of all this variation under culture belongs to no science and has no name. Botany does not claim it. Agriculture, in its restricted sense, has taken to itself the study of soils and fertilizers and domesticated animals. It comes more closely within the knowledge and practice of horticulture than elsewhere, and it may therefore very properly be called the Science of Horticulture. When Lindley wrote of the " theory of horticulture," some fifty years ago, he was disposed to refer most of this matter to "horticultural physiology." But systematic features are now fully as important as physiological, and we are inclined to designate this field of inquiry a science.

The literature of the art of horticulture is voluminous. Progress has been rapid of late years, and ample record has been made of every advancement. But in its scientific aspects, horticulture has a meagre literature. The science of horticulture may be said to have begun with the labors and writings of Thomas Andrew Knight, about the opening of the century. Knight was long the president and leading spirit of the Royal Horticultural Society of London. Various contemporaries worked in similar lines, and Dean Herbert made invaluable contributions to the knowledge of plant variation through his work in crossing and hybridizing the Amaryllid lilies. Early in the century, Joseph Hayward wrote a treatise upon the science of horticulture, and was, perhaps, the first to use and outline the term. There were few important contributions to horticultural science in the English language for many years; in fact, not until Darwin wrote "Variation of Animals and Plants under Domestication," and " Effects of Cross and Self Fertilization in the Vegetable Kingdom." Darwin never addressed his work to the horticulturist, but his was the first successful attempt to collate the scattered mass of observation of the variation of domestic plants in the one case, and to present accurate, extended and coordinated experiences of the results of cross-fertilization of vegetables in the other.