Every witness, previous to his or her obtaining any fee, except the amount which, in certain cases, must be tendered to him or her before he or she can be compelled to attend, shall give a certificate to the court wherein he or she has attended, certifying the number of days he or she has attended and the number of miles he or she has traveled; which certificate shall be subject to the examination of the court, and, if question arises, such allowance shall be made thereon as shall be lawfully due.