Michigan Compiled Laws, Chapter 600. Revised Judicature Act of 1961 § 600.2164

Sec. 2164.  (1) No expert witness shall be paid, or receive as compensation in any given case for his services as such, a sum in excess of the ordinary witness fees provided by law, unless the court before whom such witness is to appear, or has appeared, awards a larger sum, which sum may be taxed as a part of the taxable costs in the case.  Any such witness who shall directly or indirectly receive a larger amount than such award, and any person who shall pay such witness a larger sum than such award, shall be guilty of contempt of court, and on conviction thereof be punished accordingly.

(2) No more than 3 experts shall be allowed to testify on either side as to the same issue in any given case, unless the court trying such case, in its discretion, permits an additional number of witnesses to testify as experts.

(3) The provisions of this section shall not be applicable to witnesses testifying to the established facts, or deductions of science, nor to any other specific facts, but only to witnesses testifying to matters of opinion.