Page:Science (journal) Volume 1 1883.djvu/22

 water. The salt prevents the solution of the blood-globules and consequent diffusion of the red haemaglobin.

THE ORIGIN OF CULTIVATED PLANTS.

is a common saying, that the plants with which man has most to do, and which rendered him the greatest service, are those which botanists know the least. That this should hold true of the plants of immemorial cultivation, as regards both their limitation in species and their sources, is not to be wondered at. The reason why many of these cannot be identified with wild originals is because, in all probability, the originals have long been extinct. Even when spontaneous examples have been found, it is sometimes far more probable that these are the offspring of the cultivated plant relapsed into wildness, than that they are vestiges of an original stock. Indeed, plants of comparatively recent acquisition to Europe are still puzzles; of not a few the question is still open whether they originated in the new or in the old world. the herbalists and ante-Linnean botanists gave little attention to the original sources of the plants they described, and Liune still less. Following erroneous indications, he assigned the common sunflower to Peru; and its relative, the tubers of which we call artichokes, to Brazil; when he might have known that they both were sent to Europe from Canada. It is only within the present century that any considerable attempts have been made to solve such problems. Robert Brown, Humboldt, and the elder De Candolle opened the way; and Alphonse De Candolle, who has particular aptitude for this class of investigations, is one of the few who have undertaken to discuss this subject systematically. Almost thirty years ago, in his Geographie botanique raisonee (2 vols. 8vo, 1855), just before the Darwinian deluge, which swept away some of the old landmarks, and changed the face of many things, De Candolle discussed in detail the changes which have taken palce in the habitation of species, and has a long chapter on the geographical origin of cultivated plants. In this the then existing knowledge is well brought up to date, systematized, and critically treated.

This book is out of print. Greatly as it is needed, the author, who is older than he was, recoils before the labor of a new edition of the whole work. But he has taken up the subject of the origin of cultivated plants anew, and the present volume is the result.

The number of species of cultivated plants here passed in review seems at first sight to be wonderfully small, viz., only 247, or, reducing certain races to their supposed types, little over 240. But species cultivated for ornament and for medicine or for perfume are rigidly excluded; while, on the other hand, so insignificant a forage-plant as spurrey, so poor and weedy a pottage-plant as purslane, a plant which we know only in ornamental culture and for its medicinal product, castor-oil, and a fruit-tree, of such slight pomological importance as the American persimmon, are included. The latter and its old-world analogue are, indeed, only enumerated; but no one cultivates persimmons in this country. It is said that no plant of established field-culture has ever gone out of cultivation, at least in modern times, except perhaps woad; but, thanks to the chemists, madder is doomed already, and indigo is to follow.

Although Humboldt could affirm, so late as in the year 1807, that the original country of the vegetables most useful to man remains an impenetrable secret, so great progress seems to have been since made that De Condolle is able to assort his 247 species into 199 furnished by the old world, 45 by America, and only three which are still doubtful in this regard. Here the chestnut, the red currant, the common mushroom, and the strawberry are counted as of European, properly enough; since they were first cultivated in the old world, although indigenous nutritive plants worth cultivating are the sunflower-artichoke and a pumpkin, though Indian rice (Zizania) might have been turned to account if it were not for the true rice. We are not so clear as to any original inferiority, nor that these numbers might not have been more nearly equal if civilization had begun as early in the new as in the old world. Europe had the great advantage of lying adjacent to two other continents, and of being colonized from them by races which were already agricultural.

As respects the three plants of doubtful country, two are species of Cucurbita (moschata and ficifolia), comparatively unimportant and little known, which have reached Europe only recently, the latter within thirty or forty years; and the third is Phascolus vulgaris, the bean of the Americans, whose right to it we propose to claim. And we would suggest that