But a far more rapid advance in his culture condition came about when man bent his energies to the preservation, not to the destruction, of the lower animals. By the process of domestication he secured not only an abundant supply of food in their milk and flesh, but beasts of burden and draught, facilitating rapid intercourse and enabling him to conquer more rapidly the nature around him. The mental growth of many peoples has been inseparably linked to a single animal. Thus the Tartars of the steppes have their horses, the Todas their cows, the Tuaregs their camels, without which their social organisations would be wholly lost. The absence in America of any indigenous animal suited for burden or draught which could be domesticated was one of the fatal flaws in the ancient culture of the continent, drawing a line beyond which progress in many directions became impossible. _Salubrity._—By salubrity I mean the general tendency of a locality to maintain the normal functions of the body. This depends chiefly on what is included in the term “climate,” for soils become unhealthy only through the action of climatic conditions. These may be classed under three headings: 1. Temperature, which considers both the actual amount of heat and also the rapidity or extent of its variations (the “range”). 2. Moisture, including rain- and snow-fall and the average humidity. 3. Variety, not merely in the two conditions above mentioned, but of seasons, winds, clouds, electricity, etc. The last-mentioned has been too frequently overlooked or underrated by medical and ethnographic geographers. In reality, it is the most potent of the three in its results on the human body and mind. It is easy to show that it is not the extreme of heat or cold which acts injuriously on the system, but the continuance of the temperature. A climate with a marked seasonal contrast between summer and winter is confessedly more invigorating than one, no matter how delightful, which is practically the same from year-end to year-end. To keep in health, to maintain the functions in their highest relative activity, is the condition of the most effective work. Neither the individual nor the ethnic mind can reach its best results unless the body is in a healthful condition. Hence, those localities which are prone to endemic diseases or to frequent epidemics can never maintain a population intellectually equal to spots more favoured in this respect. The most marked and widespread of the endemic poisons is _malaria_, the result of a paludal germ which has not yet been isolated. Heat and moisture are requisite to its development, and immunity from it is unknown in any race.