Any corporation not for profit organized under the former General Welfare Corporation Act, or under former title 48, chapters 1-14 [repealed] for the purpose of establishing, maintaining and operating a nonprofit hospital service corporation and of providing medical benefits, whereby hospital service may be provided by a hospital or group of hospitals with which the corporation has a contract for that purpose and whereby the corporation may provide cash indemnity for medical expense, to such of the public as become subscribers to the corporation under a contract that entitles each subscriber to certain hospital care and to certain cash indemnity benefits for medical expense, shall be governed by this chapter.