The declaration of war with Mexico found him ready and willing to serve the best interests of his State and Government, by enlisting as a private soldier in a company raised in Concord. He was subsequently appointed Colonel, and finally Brigadier-General, which position he filled with honor and distinction. He sailed from Newport, the 27th of May, 1847, and remained in Mexico nine months, during which time Mrs. Pierce and her son continued at their home in Concord. Her health during his absence was not more frail than usual, but anxiety and suspense, watching yet fearing to hear of the absent one, kept her from regaining or improving her impaired constitution, and of renewing the slender chord by which her life was held. The mother of three children, none survived her, and the death of the last, under circumstances so peculiar, shattered the small remnant of remaining health, and left her mother’s heart forever desolate. On the 5th of January, previous to the inauguration of Mr. Pierce as President, an accident occurred on the Boston & Maine Railroad, which resulted in a great calamity; among the passengers were the President-elect, his wife, and only son, a bright boy of thirteen years. The family were on their return to Concord from Boston, and it was between Andover and Lawrence that the axle of one of the passenger-cars broke, and the cars were precipitated down a steep embankment. Mr. Pierce, sitting beside his wife, felt the unsteady movements of the train and instantly divined the cause. Across the seat from them sat their son, who but a moment ago was amusing them with his conversation. A crash, a bounding motion as the cars were thrown over and over down the hill, and men began to recover from their fright and assist in aiding those injured in the fearful accident. Mr. Pierce, though much bruised, succeeded in extricating his wife from the ruins, and bearing her to a place of safety, returned to hunt his boy. He was soon found; his young head crushed and confined under a beam, his little body still in death. Even now it is a subject too painful to dwell upon. What must have been the feelings of those grief-stricken parents, in a moment bereft of their all! The remains were conveyed to Andover until arrangements could be made for their removal to Concord. Under such a bereavement, in feeble health and exhausted vitality, came Mrs. Pierce to the White House. Through the season, before her great trial was sent upon her, she had been nerving herself for the undesired duties and responsibilities of her public station at Washington; and with the burden of that crushing sorrow she went forward, with the noblest self-sacrifice, to do what was to be done, as well as to bear what was to be borne. That she performed her task nobly and sustained the dignity of her husband, the following letter will prove.