In many Indian myths we read how the shamans, singly or in companies, seek the Spirit-Land, either to search for the souls of those who are ill, but not yet dead, or to seek advice from supernatural beings. These thaumaturgical practices were usually undertaken by three medicine men in concert. Falling into a trance, in which their souls were supposed to become temporarily disunited from their bodies, they would follow the track of the sick man's spirit into the spirit-world. The order in which they travelled was determined by the relative strength of their guardian spirits, those with the strongest being first and last, and he who had the weakest being placed in the middle. If the sick man's track turned to the left they said he would die, but if to the right, he would recover. From the trail they could also divine whether any supernatural danger was near, and the foremost priest would utter a magic chant to avert such evils if they came from the front, while if the danger came from the rear the incantation was sung by the priest who came last. Generally their sojourn occupied one or two nights, and, having rescued the sould of the patient, they returned to place it in his body.
Not only was the shaman endowed with the power of projecting his own 'astral body' into the Land of Spirits. By placing cedar-wood charms in the hands of persons who had not yet received a guardian spirit he could impart them his clairvoyant gifts, enabling them to visit the Spirit-land and make any observations required by him.
The souls of chiefs, instead of following the usual route, went directly to the sea-shore, where only the most gifted shamans could follow their trail. The sea was regarded as the highway to the supernatural regions. A sick man was in the greatest peril at high water, but when the tide was low the danger was less.
The means adopted by the medicine-men to lure ghosts away from their pursuit of a soul was to create an 'astral' deer. The ghosts would turn from hunting the man's soul to follow that of the beast.
"Myths of the North American Indians" by Lewis Spence.