Section 8. Each superintendent shall before entering upon his duties give bond to the commonwealth, with sureties approved by the governor and council, in such sum as the comptroller may prescribe, conditioned that he shall faithfully perform all his duties and account for all money received by him as superintendent. The bond shall be filed in the office of the state treasurer. Each superintendent shall have charge of all the property of the institution within the precincts thereof. He shall keep accounts of all his receipts and expenditures, and of all property intrusted to him, showing the income and expenses of the institution; and shall account to the commissioner of youth services, in such manner as said commissioner may require, for all money received by him. His books and all documents relative to the school shall at all times be open to the inspection of the commissioner of youth services.