Section 74. No mutual fire company operating on the cash premium plan as provided in section eighty-one, nor any mutual fire company with a guaranty capital of less than the combined capital and surplus provisions required under section forty-eight, either of which has become insolvent, or through reinsurance or cancellation or expiration of risks has on its books less than one million dollars of insurance in force, not reinsured, or has less than four hundred separate risks in the commonwealth, shall make any further insurance until it has secured applications for policies which, together with the unreinsured risks in force, shall amount to not less than one million dollars in not less than four hundred separate risks in the commonwealth, said applications to be subject to the provisions of the preceding section applying to the subscriptions for insurance in a new company; provided, that whenever such reinsurance has been effected for the purpose of reducing the company’s liability on account of excessive loss, the number and amount of said applications for policies shall not be required within one year thereafter. Upon the filing of applications under this section with the commissioner, he may make such investigation as he deems proper, and, if his findings warrant it, grant a certificate to such company to issue policies.