The indorsement of the note by the defendant Cherrington, under the circumstances proved, imported a guaranty of the payment of the note to the plaintiff, and gave *531him authority to write, over her name, the contract implied by law; and this, if necessary at all, could be done during the trial. Josselyn v. Ames, 3 Mass. 274. Tenney v. Prince, 4 Pick. 385.

The finding of the court renders immaterial the question whether demand and notice were necessary.

Judgment for the plaintiff.