Mississippi Code Title 41. Public Health § 41-37-21

The physician performing the autopsy or the chemist performing such analysis in criminal investigations may be subpoenaed as a witness in any such criminal case. If subpoenaed as a prosecution witness, he shall be paid a fee of Fifty Dollars ($50.00) per day as an expert witness for each day while in attendance at the trial, and in addition thereto he shall be paid Seven Cents (7¢) per mile for travel from his home to the location of the trial and return. The fees herein provided for shall be paid to prosecution witnesses as otherwise provided for by law for the payment of such witness fees. If subpoenaed as a witness by the defense, such physician or chemist may collect a fee from the defendant not to exceed that prescribed hereunder for prosecution witnesses.