Section 55. Mutual companies organized prior to April sixth, nineteen hundred and eleven, to transact employers' liability insurance may continue such business under the sixth clause of section forty-seven. They may also transact all the kinds of business specified in the said sixth clause if authorized so to do by a vote of two thirds of the policyholders present and voting at a meeting called therefor.

Mutual companies organized prior to March first, nineteen hundred and fifteen, to transact steam boiler insurance may transact all the kinds of business specified in the fifth clause of section forty-seven.