1. While the defendant has made no motion to dismiss the writ of error, it is not only the right but the duty of a reviewing court to raise the question of its jurisdiction in all cases in which there may be any doubt as to the existence of such jurisdiction. Welborne v. State, 114 Ga. 793, 796 (40 S. E. 857); Davis v. State, 191 Ga. 558 (13 S. E. 2d 351); Milner v. Sunbeam Heating Co., 44 Ga. App. 221 (2) (160 S. E. 822); Durrell v. White, 198 Ga. 253 (31 S. E. 2d 461).

2. By the terms of Code (Ann.) § 87-818, exception must be taken to a judgment validating revenue-anticipation certificates within 20 days from such judgment, and, where the Superior Court of Camden County enters an order validating water revenue certificates of the City of Woodbine on February 16, 1957, and exception is not taken to such judgment until March 16, 1957 (a period of 28 days) this court is without jurisdiction to review that judgment.

Writ of error dismissed.