Sec. 4. A hospital described in this chapter must be open to all of the following:
(1) Persons on reasonable terms.
(2) Physicians on reasonable terms who desire to place patients in the hospital.
(3) Employees of the city, without charge, who are injured in the course of employment.
(4) Poor and indigent persons on reasonable rates to be paid by the proper officers having charge of the care of those persons.