In 1835, Mr. Davis, sickened of military life without the excitement of actual engagement with an enemy, and retired from the service, settling down upon a cotton plantation in Mississippi. For nearly ten years he remained on his plantation in quiet, cultivating cotton and his intellect at the same time, for he was during all these years of rural life a great student and reader. He was contentedly preparing himself for the future occasion which should call for his services. In 1843, he took the stump for Mr. Polk, and such was his ability before the people that they sent him to Congress in 1845. When he had been in Washington but a few months, the war with Mexico broke out, and his constituents raised a regiment of volunteers, who elected Mr. Davis as their colonel. He immediately resigned his seat in Congress, and went with his regiment to join General Taylor in Mexico. The history of Col. Davis' career in Mexico is full of interest, but we cannot stay to elaborate it. At Buena Vista he won laurels of glory, in the parlance of the soldier. Says a friend of his: "His men--though volunteers--showed a steadiness which equalled anything that might have been expected of veteran troops; and they were handled in so masterly a way, that, if the glory of that day were to be assigned to any one corps rather than any other, they would probably bear away the palm. Every one remembers the proud appeal of Colonel Davis to another regiment of volunteers, who were finding the fire rather warm, to 'Stay and re-form behind that wall'--pointing to his Mississippians. Throughout the war, he and his brave riflemen loom up at intervals whenever the fire grows hot or the emergency grave, and never without good effect. They were armed with a peculiar rifle, now best known as the Mississippi rifle, chosen by their colonel himself; it was scarcely less deadly than the Minié. Their colonel set the example of intrepidity and recklessness of personal injury: at Buena Vista he was badly wounded at an early part of the action; but he sat his horse steadily till the day was won, and refused even to delegate a portion of his duties to his subordinate officers." The term of service for which his regiment was enlisted having expired, his medical advisers insisted upon his going home and curing himself of his wounds. He did not stay long, however; for that very year--in the late autumn--he was appointed United States Senator by the Governor of Mississippi to fill a vacancy, and when the legislature of the State came together, it elected him to the same high office for the ensuing six years.