The offer was declined on account of the deep snows which prevented a march; but the incident made friends for white men, and the tidings of it had a wholesome effect on the other tribes.
"The whole religion of the Mandans," like that of many other savage tribes, says the journal, "consists in the belief of one Great Spirit presiding over their destinies.

This Being must be in the nature of a good genius, since it is associated with the healing art, and 'great spirit' is synonymous with 'great medicine,' a name applied to everything which they do not comprehend.

Each individual selects for himself the particular object of his devotion, which is termed his medicine, and is either some invisible being, or more commonly some animal, which thenceforward becomes his protector or his intercessor with the Great Spirit, to propitiate whom every attention is lavished and every personal consideration is sacrificed.

'I was lately owner of seventeen horses,' said a Mandan to us one day, 'but I have offered them all up to my medicine and am now poor.' He had in reality taken all his wealth, his horses, into the plain, and, turning them loose, committed them to the care of his medicine and abandoned them forever.

The horses, less religious, took care of themselves, and the pious votary travelled home on foot." To this day, all the Northwest Indians speak of anything that is highly useful or influential as "great medicine." One cold December day, a Mandan chief invited the explorers to join them in a grand buffalo hunt.