§ 171. Powers and duties of commissioner. The commissioner of charities shall have the general care, management, administration and supervision of the charities, almshouses, hospitals, houses of correction, orphan asylums and all other similar institutions, the control or government of which belongs or is intrusted to the city. He shall make regulations for the expenditure of the moneys appropriated for the support or relief of the poor and for the general supervision of such expenditures. He shall investigate fully the circumstances of all persons alleged to be destitute or without proper means of support, or without proper guardianship, or who are in danger of becoming or are a public burden in any respect; and also the circumstances of their relatives or other persons whose duty it is to relieve or maintain them or contribute to their support; also to institute and prosecute any and all actions and proceedings authorized by law to compel any and all persons liable for the care, maintenance, education or support of any such destitute or dependent persons to contribute thereto, and to indemnify the city and public against any expenditures on account thereof. He shall also prosecute any and all bonds, undertakings or recognizances given for any of the purposes herein mentioned or in any manner relating thereto. Any and all moneys recovered in any such suit, action or proceeding or otherwise paid to or received by the said commissioner on account of the care, maintenance, relief, education or support of any such persons shall be deposited by the commissioner with the city treasurer as a trust fund, and the same shall be applied and expended by the said commissioner for the purpose on account of which the same were paid. Any surplus remaining in said fund at the close of the fiscal year shall be treated as an unexpended balance of money appropriated for such department. The commissioner shall furnish to and file with the comptroller a monthly statement in detail of all receipts and expenditures, including the aid and relief granted by him, with the names and addresses of all recipients.