Section 52. The determination by the department, under the provisions of section forty-eight of chapter one hundred and sixty and section twenty-eight of chapter one hundred and sixty-one, as to the amount of stock which is reasonably necessary for the purpose for which such stock has been authorized shall, in the case of the corporations described in section fifty, be based upon the price at which such stock is to be issued as fixed by the stockholders; but the department shall refuse to approve any particular issue of stock if, in its opinion, the price fixed by the stockholders is so low as to be inconsistent with the public interest.