Mrs. Mowatt was never behind the scenes of a theatre until she was taken to witness a rehearsal of _Fashion_ the day before its first production. Her second passage through a "stage door" was when she had her single rehearsal of _The Lady of Lyons_, in which she made her _debut_, and she became an actress, and a triumphant one, three weeks after her determination to go upon the stage was formed. Her house was crowded, the applause was genuine and discriminating, and one gentleman, wholly unprejudiced and of great experience, publicly pronounced it "the best first appearance" he ever saw. The performance took place at the Park Theatre, New York, on the 13th of June, 1845, less than three months after the production of her comedy. The occasion was the benefit of Mr. Crisp, who had given her the little instruction her limited time permitted her to receive, and who played Claude to her Pauline, Mrs. Vernon representing Madame Deschapelles. While she writes candidly in her _Autobiography_ of her hopes, her experiences, and her trials, she modestly says but little of the decided praise from all quarters which she certainly received, the account of her success here given being taken from current journals and from the recollections of old theatre-goers, not from her own story of her theatrical life. On the 13th of July of the same year (1845) Mrs. Mowatt appeared at Niblo's Garden, playing a very successful engagement of two weeks, supported by Messrs. Crisp, Chippendale, E. L. Davenport, Thomas Placide, Nickinson, John Sefton, and Mrs. Watts, afterwards Mrs. Sefton. Here she assumed her second _role_, that of Juliana in the _Honeymoon_, and more than strengthened the favorable impression she had made as Pauline. During the first year she was upon the stage she acted more than two hundred nights, and in almost every important city in the United States, playing Lady Teazle, Mrs. Haller in _The Stranger_, Lucy Ashton in the _Bride of Lammermoor_, Katherine in the _Taming of the Shrew_, Julia, Juliet, and all of the then most popular characters in the line of juvenile tragedy and comedy. The amount of labor, physical and mental, she endured during this period must have been enormous; and the intellectual strain alone was enough to have destroyed the strongest mental constitution. In the history of the stage in all countries there is no single instance of a mere novice playing so many important parts so many nights, before so many different audiences, and winning so much and such merited praise, as did this lady during the first twelve months of her career as an actress.