Section 12. No officer of a prison shall, nor shall any person in trust for or employed by him, have any interes

12. No officer of a prison shall, nor shall any person in trust for or employed by him, have any interest, direct or indirect, in any contract for the supply of the prison: nor, except so far as is expressly allowed by rules made under section fifty-four, shall he derive any benefit, directly or indirectly, from the sale of any article on behalf of the prison or belonging to a prisoner. Superintendent.