Introduction

Man reclaims, disciplines and trains Nature. The surface of Europe, Asia and North America has submitted to this influence and discipline, but it still has to be applied to large parts of South America and Africa. Marshes must be drained, forests skillfully thinned, rivers be taught to run in ordered courses and not to afflict the land with drought or flood at their caprice; a way must be made across deserts and jungles, war must be waged against fevers and other diseases whose physical causes are now mostly known. ¹