It is here maintained that it is the letting go, little by little, the correct views of living, which causes the white race to deteriorate, and not the climate. The necessities of life are fewer and easier to obtain in hot countries than in cold ones; and this makes it easy for men to become indolent, to lose ambition and to sink to a low level of living and thinking. The Tropics, contrary to the usual view, are healthful regions. Malaria exists in hot countries, but so it does in temperate ones. Typhoid fever and contagious diseases are no worse than in cold climes. Smallpox is regarded as a mild disease. Scarlet fever is said not to exist at all. Where filth is allowed to accumulate disease prevails, but in lands well drained and free from decaying matter and filth, there is, under ordinary care, no more to be feared from disease than in the most favored portions of the earth. At present, in hot countries the people pay little attention to sanitation. As a rule, they are unutterably dirty. They live in their own filth, and seem to enjoy it. The germs of disease from one body are promptly taken into another before they have time to die, or are cultivated in filth deposits until the whole community is affected. The Tropics, in themselves, are no more and no less healthful than temperate regions. But the people in cold countries have some respect for sanitation, while those in hot countries have very little or no respect for decent cleanliness. This is the whole explanation of this matter. People who have the latrine in the kitchen and uncleaned for a century, who sleep in rooms into which a breath of fresh air cannot enter; who seldom wash their bodies; who use rum and tobacco instead of food; who permit children to cohabit promiscuously, can scarcely hope to escape disease, if any prevails in their neighborhood. Such conditions are the rule with the masses in hot countries. Those who become ‘acclimatized’ will be able to live in hot countries. It is doubtful whether or not there is any actual condition known as ‘acclimatization,’ although if the term means becoming accustomed to filth, and to certain germs which live in filth, there may be something in the term. Instead of a bodily change, the individual gradually becomes educated to his new environment. He learns what to eat and drink, what to wear and where to sleep, when and how much to work, to come in out of the shower and to change his wet clothes, to avoid the midday sun and the damp air of the night. When a man new to the Tropics has learned these things, he is ‘acclimatized.’ Some learn them at once; others are years in learning, and meanwhile suffer from sickness and distress.