The thrilling incidents with which the annals of Fort McKenzie abounded in these early years would fill a volume; but we can note only the more important. The year 1837 was the year of the terrible smallpox scourge among the tribes of the Missouri Valley. Great care was taken at Fort Union to dispatch the annual outfit for Fort McKenzie without carrying the smallpox along with it. The expedition was in charge of Alexander Harvey, one of the most noted and desperate characters which the fur trade produced. Harvey took every possible precaution, but in spite of his efforts the disease broke out in his party. He therefore thought it prudent to stop before he reached Fort McKenzie and send word to Culbertson, who had been in charge of the fort since 1834, when Mitchell left. Culbertson wisely decided to leave the cargo at the mouth of the Judith until the disease had run its course. There were large numbers of Indians encamped near the fort awaiting the arrival of the boat, and when they learned of the proposed delay they became suspicious and insisted that the boat should be brought up. Culbertson expostulated with them, but all in vain, and to avoid the capture and destruction of the boat and its crew, he yielded to their demands. [Sidenote: TERRIBLE MORTALITY.] The result was exactly what had been foreseen. The disease was communicated to the inmates of the post and to the Indians as well. The latter completed their trade and left the fort before the pest actually broke out among them, and the garrison remained for some time in ignorance of what their fate had been. For upwards of two months not an Indian was seen, and Culbertson, fearing the dreadful truth, resolved to go in search of them. With a single companion he set out for the Three Forks of the Missouri, where the Piegans usually spent their autumns hunting beaver. They finally came upon a village of about sixty lodges, only to find it absolutely deserted, with dead bodies strewn in every direction, and carrion birds of prey the only sign of life anywhere around. The smallpox had done its work well, and the few survivors of the village had fled in scattered groups among the surrounding mountains. The mortality among the Bloods and Blackfeet had been as great as among the Piegans, and Culbertson estimated the total loss among the three bands at six thousand souls. The Grosventres, for some cause, escaped with small loss.