¹[510. Any document purporting to be a report under the hand of any Chemical Examiner or Assistant Chemical Examiner to Government or any serologist, handwriting expert, finger print expert or fire-arm expert appointed by the Government, upon any matter or thing duly submitted to him for examination or analysis and report in the course of any proceeding under this Code, may, without calling him as a witness, be used as evidence in any inquiry, trial or other proceeding under this Code.]