Section 33. The Bristol county agricultural school and the Norfolk county agricultural school shall be free to residents of Bristol and Norfolk counties, respectively, over 14 years of age, except that free attendance shall be limited by the capacity of the courses provided for such schools. The trustees of the Bristol county agricultural school and Norfolk county agricultural school may require the payment of tuition and related fees from each person enrolled in adult evening courses offered by said schools. The amount of tuition and related fees shall be determined by said trustees. All receipts of such tuition and related fees shall be deposited with the treasurer of the county.