ultra-democratic elements, may become most dangerous enemies to rational liberty, to the moral interests of the commonwealth, to the purity of legislation and of judicial action, and to the sacredness of private rights.] The geological, hydrographical, and topographical surveys, which almost every general and even local government of the civilized world is carrying on, are making yet more important contributions to our stock of geographical and general physical knowledge, and, within a comparatively short space, there will be an accumulation of well established constant and historical facts, from which we can safely reason upon all the relations of action and reaction between man and external nature. But we are, even now, breaking up the floor and wainscoting and doors and window frames of our dwelling, for fuel to warm our bodies and to seethe our pottage, and the world cannot afford to wait till the slow and sure progress of exact science has taught it a better economy. Many practical lessons have been learned by the common observation of unschooled men; and the teachings of simple experience, on topics where natural philosophy has scarcely yet spoken, are not to be despised. 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 takes account of organic life--Geographical importance of plants--Origin of domestic vegetables-Transfer of vegetable life--Objects of modern commerce-Foreign plants, how introduced--Vegetable power of accommodation--Agricultural products of the United States--Useful American plants grown in Europe--Extirpation of vegetables--Animal life as a geological and geographical agency--Origin and transfer of domestic quadrupeds--Extirpation of wild quadrupeds--Large marine animals relatively unimportant in geography--Introduction and breeding of fish--Destruction of fish--Geographical importance of birds--Introduction of birds--Destruction of birds--Utility and destruction of reptiles--Utility of insects and worms--Injury to the forest by insects--Introduction of insects--Destruction of insects--Minute organisms. MODERN GEOGRAPHY EMBRACES ORGANIC LIFE.