Any number of persons, not less than thirteen, may associate and form a company for the purpose of making insurance upon the lives of individuals, and every assurance pertaining thereto or connected therewith (including, for policies issued outside of the United States of America, insurance of nonlife risks that are attached as riders to policies insuring the lives of individuals; provided that the aggregate premium assumed on an annual basis pursuant to such nonlife risks does not exceed three percent of the capital and surplus of such company as of the thirty-first day of December of the preceding year), and to grant, purchase and dispose of annuities and endowments of every kind and description whatsoever, and to provide an indemnity against death, and for weekly or other periodic indemnity for disability occasioned by accident or sickness to the person of the insured; but such accident and health insurance shall be made a separate department of the business of the life insurance company undertaking it.