If climate were responsible for health to the degree that its enthusiasts believe, how are we to account for the amount of sickness, early aging and physical inefficiency seen in the most favorable climatic areas, such as the northeastern quarter of the United States and England, and the fine physical development of the Arabs and the pastoral tribes of Asia, whose climate is less stimulating? The teeth of the Americans and English of the present generation are indescribably bad, even where the climate is held to be best adapted to health, and to the promotion of physical and mental activity. What stands in the way of progress of Asiatic and African peoples which has kept them far behind the Europeans and Americans in advancing learning? It seems more plausible to regard the failure of certain peoples to progress as primarily a geographic one quite as much as climatic. The nature of the land, and its rainfall determine the character and vigor of the vegetation, and indirectly the character of the diet. Climate determines the kind of agriculture which is profitable, and, therefore, the most satisfactory mode of life of the people of any region. Conditions of living are often so hard that the vitality of every individual is taxed to the utmost to secure the primary physical needs for food, clothing and shelter. In the case of the herdsman his constant activity in the open denies him the opportunity to invent machinery or to develop experimental sciences. He never feels the need for these, because of his mode of life. Climate does not necessarily prevent his advance, except indirectly through determining his mode of life and the things upon which he will fix his thoughts. There is little prospect that an arid region can be utilized in any other manner than through raising animals on its scanty pasturage, so it seems impracticable to attempt to make anything out of such places except what they are. It is, however, quite another matter when we turn to tropical regions, with their unlimited possibilities for agriculture. Are we to accept the gloomy picture which Huntington draws for us of the utter hopelessness of making the tropics the abode of human culture? I am not convinced that this problem is an insolvable one.