Compelling of appearance and testimony of expert witnesses.

A witness who is an expert in any art, science, trade or profession may be compelled to appear and testify to an opinion as such expert in relation to any matter whenever such opinion is material evidence relevant to an issue on trial before a court or jury without payment or tender of compensation other than the per diem and mileage allowed by law to witnesses under the same rules and regulations by which he can be compelled to appear and testify as to his knowledge of facts relevant to the same issue.

(Code 1923, §7713; Code 1940, T. 7, §366.)