In these humble pages, which do not in the least aspire to rank among scientific expositions of the laws of nature, I shall attempt to give the most important practical conclusions suggested by the history of man's efforts to replenish the earth and subdue it; and I shall aim to support those conclusions by such facts and illustrations only as address themselves to the understanding of every intelligent reader, and as are to be found recorded in works capable of profitable perusal, or at least consultation, by persons who have not enjoyed a special scientific training. CHAPTER II. TRANSFER, MODIFICATION, AND EXTIRPATION OF VEGETABLE AND OF ANIMAL SPECIES. MODERN GEOGRAPHY EMBRACES ORGANIC LIFE--TRANSFER OF VEGETABLE LIFE-- FOREIGN PLANTS GROWN IN THE UNITED STATES--AMERICAN PLANTS GROWS IN EUROPE--MODES OF INTRODUCTION OF FOREIGN PLANTS--VEGETABLES, HOW AFFECTED BY TRANSFER TO FOREIGN SOILS--EXTIRPATION OF VEGETABLES-- ORIGIN OF DOMESTIC PLANTS--ORGANIC LIFE AS A GEOLOGICAL AND GEOGRAPHICAL AGENCY--ORIGIN AND TRANSFER OF DOMESTIC ANIMALS--EXTIRPATION OF ANIMALS--NUMBERS OF BIRDS IN THE UNITED STATES--BIRDS AS SOWERS AND CONSUMERS OF SEEDS, AND AS DESTROYERS OF INSECTS--DIMINUTION AND EXTIRPATION OF BIRDS--INTRODUCTION OF BIRDS--UTILITY OF INSECTS AND WORMS--INTRODUCTION OF INSECTS--DESTRUCTION OF INSECTS--REPTILES-- DESTRUCTION OF FISH--INTRODUCTION AND BREEDING OF FISH--EXTIRPATION OF AQUATIC ANIMALS--MINUTE ORGANISMS. _Modern Geography embraces Organic Life._ It was a narrow view of geography which confined that science to delineation of terrestrial surface and outline, and to description of the relative position and magnitude of land and water. In its improved form, it embraces not only the globe itself, but the living things which vegetate or move upon it, the varied influences they exert upon each other, the reciprocal action and reaction between them and the earth they inhabit. Even if the end of geographical studies were only to obtain a knowledge of the external forms of the mineral and fluid masses which constitute the globe, it would still be necessary to take into account the element of life; for every plant, every animal, is a geographical agency, man a destructive, vegetables, and even wild beasts, restorative powers. The rushing waters sweep down earth from the uplands; in the first moment of repose, vegetation seeks to reestablish itself on the bared surface, and, by the slow deposit of its decaying products, to raise again the soil which the torrent had lowered. So important an element of reconstruction is this, that it has been seriously questioned whether, upon the whole, vegetation does not contribute as much to elevate, as the waters to depress, the level of the surface.