Wait, J.
The defendants are sureties upon a bond given to dissolve an attachment made in an action brought by Joseph Aronow against one Hyman Doodlesack, the principal in the bond. They contend that they were discharged of liability when, without notice to them, certain amendments to the declaration filed in the suit of Aronow v. Doodlesack were made and allowed.
G. L. c. 231, § 51, provides that the court “at any time before final judgment, except as otherwise provided, . . . may allow any other amendment in matter of form or substance in any process, pleading or proceeding, which may enable the plaintiff to sustain the action for *68the 'cause for which it was intended to be brought, or enable the defendant to make a legal defence.” Section 138 of the same chapter provides that “ no . . . bail or any person other than the parties, to the record shall be bound by such allowance unless he has had due notice of the application for leave to amend and opportunity to be heard thereon.” A long line of decisions has established that the effect of these statutes is to retain the security of an attachment and of a bond given to dissolve an attachment when the judgment is for the same “ cause of action relied on by the plaintiff when the action was commenced,” even though the claim may at first have been misdescribed. Driscoll v. Holt, 170 Mass. 262, 265. Lack of notice to the surety does not put an end to his responsibility if the amendment does not subject him to a different burden from the one he undertook when he executed the bond. That burden was to meet the judgment for the cause for which the action was brought. A change of parties may affect his liability. We cite only a few of the many cases. Tucker v. White, 5 Allen, 322. Driscoll v. Holt, supra. Morton v. Shaw, 190 Mass. 554. Salvin v. Sidman, 230 Mass. 278. Savage v. Welch, 246 Mass. 170, 178 et seq.
In the case before us the causes of action for which the two counts of the declaration sought recovery were the failure to pay the balance-due for plumbing and heating materials supplied for and labor upon certain buildings; and for labor and materials for remodelling the heating and plumbing equipment in certain other buildings. No contention is made that the second count has been affected by amendment. At the trial a change in statement was thought desirable from a demand for a balance of $1,500 due under a written contract, modified in certain respects by agreement, and alleged to be fully performed by the plaintiff, to a demand on quantum meruit for work and materials furnished in rendering the identical service. Further it appeared that a note for $800 had been given on account of the $1,500. An amendment to the first count was made giving credit for that amount on the balance, and *69a new count upon the note was added. Later, this new count and the first count as amended were waived. The case rested finally upon the original second count and the count on quantum meruit added by amendment. Thus in no way was anything sought in the pleadings which had not been claimed in substance in the unamended pleadings. Whether splitting the balance of $1,500 cash originally claimed into $700 cash and an unpaid note for $800 given on account of that balance introduced a new cause of action need not be considered. The amendment was made during the progress of the trial and was waived before the trial ended. Such momentary change ought not, we think, to be given the serious consequence of discharging sureties actually not affected by it.
Lack of notice of the allowance of the amendments imposed no hardship upon the sureties. Their initial liability was not affected to their detriment by the amendments.
Exceptions overruled.