Michigan Compiled Laws, Chapter 331. Hospitals § 331.163

Sec. 13.  All physicians and surgeons licensed under the laws of Michigan shall have the privilege of treating patients in the hospital, subject always to such rules and regulations as shall be established by the board of trustees under the provisions of this act.  The patient shall have the right to employ at his own expense his own physician or nurse, and when acting for any patient in such hospital the physician employed by the patient shall have charge of the care and treatment of such patient.