An Act amending the "Pennsylvania Municipal Retirement Law," approved February 1, 1974 (P. L. 34, No. 15), providing that a person receiving a retirement allowance be a member of the Pennsylvania Municipal Retirement Board and further providing for the actuarial soundness of the fund, for excess interest, for payment of administrative funds from excess interest earnings, for member's excess investment account, for excess investment earnings, for joining the fund, for municipal liability, for credit for other governmental service, for contributions, for return to service and for computation of benefits.