“Sweating is strictly a part of the devotional observances of the Apsaroke, practised not for material cleanliness, but for such purification as will make their bodies acceptable to the spirits. Young men rarely enter the sweat-lodge except when they desire to purify themselves for the four days’ fast in the mountains. Close by every dwelling even to-day can be seen the sweat-lodge where men and women go together for ordinary devotion and for special occasions. It is a sacred spot, where frivolity is not to be thought of. The most important of their ceremonial sweats was Awúśh-balipē, the Medicine Sweat-lodge, which belonged only to great war-leaders. It was said that in their fasting the spirits gave them the rights of this ceremony along with their other medicine. When such a man was ready to lead a war-party, he would tell those who wished to join him to cut willows: four strong large ones about an inch in diameter, and one hundred smaller ones. The four large ones were thrust into the ground and bent to form two parallel arches. Then the hundred were planted to complete the circle, crossing the arches, fifty on each side, making a framework some seven feet in diameter. In its centre was dug the pit for the heated stones, and around it the grass was cut away for about eight inches. From there to the opening the grass was removed, so that the earth exposed was in the shape of an eagle-tail, and the rest of the ground was covered with sage. An entire buffalo-robe was thrown over the lodge after the frame had been covered, the tail hanging downward at the back, and the nose in front, facing the east. On the top of the robe were placed the war-leader’s medicine, a holy pipe, and a tobacco medicine-bag, these last two not necessarily the property of the priest. Other war-leaders now came and deposited their medicine with that of the priest, the one who was to receive the heated stones and begin the pouring of the water placing his nearest the door. Those who were to participate in the sweat entered and sat down, war-leaders on the right and warriors that stood high in the estimation of the leader of this party on the left, while those who intended to accompany the party, but were not prominent enough to have a seat in the sweat-lodge, passed in the heated stones, one at a time. Not a word was spoken inside as the first three were handed in, but when the fourth was received by the old leader at the door and placed in the pit, each man made a feint as if seizing it in his hands and drawing it to him, at the same time expressing some wish, such as, “May I take a horse!” “May I kill an enemy!” “Here comes the enemy’s gun!” When all the stones were in and the cover down, water was poured on from a horn cup four times, and as the steam arose, the leader began to sing, all joining with him. After singing four times, he said, “Throw the door up,” and as the cover was raised he told a dream in which he had seen a certain season, and each person prayed briefly that he himself might live until that time. Then the leader spoke: “I have said! Close the door.” When the cover was down he poured water seven times, and the one at his left sang his song four times, the rest joining. Then the door was raised again. Next he poured water ten times, and the second at his left sang four times, and finally the leader poured the remainder of the water on the stones, while the third man sang his song four times. Then the door was raised for the last time, and all came out slowly and went into the stream. When a man had a vision of the sweat-lodge of a hundred sticks, he went at once to a war-leader who owned the medicine and employed him to make the lodge. When there was need of haste in taking the war-path, the hundred-stick lodge could not be built, so a few small sticks were hastily made into a miniature sweat-lodge, and placed in a lonely spot as an offering symbolizing their observance of the ceremonial purification.”
From Volume IV of Edward S Curtis’ The North American Indian