As I have already intimated, the Indian is practically an out-of-door sleeper. I say “practically,” for there are exceptions to the general rule. The Hopis of northern Arizona have houses. In the cold winter months they sleep indoors whenever they can. The Navahos, Apaches, Havasupais, and other tribes have their “hogans” and “hawas” in which they sleep in the very cold weather. But in the summer the invariable rule is for all to sleep out of doors. And even in the winter, if duty calls them away from home and they have to camp out, they sleep in the cold, on the snow, in the rain, as unconcerned for their health as if they were well protected indoors. It is this latter feature that so much commends itself to me. It is just as _natural_ to them to have to sleep out of doors as it is to sleep indoors. They think no more of it, do not regard it as an unusual and dangerous experience, or one to be dreaded. They accept it without a murmur or complaint, and without fear. This is an attitude of mind that I would the white race would learn from the Indian. I once had a friend, a city-bred man, born and brought up in New York, sent west to me by his physician because he had had two or three hemorrhages, whom I took out into Arizona. The first night we had to sleep out was very cold, for it was early in the year, and at that high altitude the thermometer sank very rapidly after the sun went down. Yet I deliberately called camp by the side of a great snowbank. The fearful invalid wanted to know what I was stopping there for. I told him it was to afford him a good sleeping place on the snow. He expressed his dread, and assured me that such an experience would kill him at once. I told him that if it did I would see that he was decently buried, but that did not seem to dissipate his fears. After a good camp-fire was built, and he had had a warm and comforting supper, and his blankets were stretched out on the snow, and he was undressed and well wrapped up, with a hot rock at his feet and the cheery blaze lighting up the scene, he felt less alarmed. I talked him to sleep, and when he awoke in the morning it was to confess that his throat and lungs felt more comfortable than they had done for many long months. A month of this open-air sleeping gave him new ideas on the subject, and sent him back east to fit up a camp in the Adirondacks, where he could get a great deal of outdoor life, and sleeping with doors and windows wide open. [Illustration: BOSTON MILLIONAIRES SLEEPING OUT OF DOORS ON THE SANDS OF THE COLORADO RIVER.] The outdoor treatment for tuberculosis is now almost universal. Here is what one eminent authority says on the subject: