Said reserve shall be established by setting aside a sum equal to ten per cent of the premium (that is the sum charged for insurance over and above examination and settlement fees) paid on each policy of insurance which such company may hereafter issue, until the total amount set aside shall equal two hundred and fifty thousand dollars: Provided, That the said total reserve fund may, with the consent of the secretary, be set aside at any one time, or from time to time, out of surplus and undivided profits. Said ten per cent of each premium shall be known as the reserve, and the aggregate of said reserves of all policies issued and outstanding shall be known as the reserve fund. The reserve fund shall be maintained as herein provided so long as liability on any policies shall be outstanding.