Mass. Gen. Laws ch. 149, § 67: Days and hours of work for boys or girls under eighteen

Section 67. Except as limited by section fifty-six, no person shall employ a boy or a girl under eighteen or permit such a boy or girl to work in, about or in connection with any establishment or occupation named in section fifty-six or sixty for more than six days in a week, or more than forty-eight hours in a week, or more than nine hours in a day, and, if the work performed by such boy or girl in a day is not continuous but is divided into two or more periods, the person employing such boy or girl shall so arrange his or her work that all such periods shall fall within a period of twelve consecutive hours.