Alone, and crossing an open plain swarming with wolves, he was seized suddenly with a violent colic, the pain of which was so terrible that he could not remain in the saddle.

He dismounted, hobbled his horse, and threw himself on the grass, where he lay in agony for two hours, expecting every moment would be his last, till, quite exhausted, he fell asleep.

He was awakened, however, by the howling of the wolves advancing to tear him to pieces; yet he was so weak that he was scarcely able to mount his horse, and then could only proceed at a slow walk, with the wolves snapping at his horse's heels.
Near the site of the present city of Winnipeg, in the late summer of 1800, he and his expedition were much troubled by swarms of water snakes.

They were harmless but not pleasant in their familiarity, for they entered the tents and took refuge in the explorers' beds; and as they apparently came from their breeding places in Amerindian graves which covered the remains of people who had died of smallpox in a recent epidemic, they were additionally loathsome.
Smallpox indeed played a very important part in the historical development of western North America.

Prior to 1780 the Amerindian tribes between the upper Mississippi and the Rocky Mountains, and between the Saskatchewans and the Missouri, were numerous and warlike.
At first, about 1765, they received in very friendly fashion the pioneer British traders and French Canadians who attempted to resume the fur trade where it had been dropped by the French monopolists in 1760.