Any document purporting to be,-
(a) a certificate under the hand of a Registered Medical Practitioner or the Chemical Examiner or Assistant Chemical Examiner to Government under section 109 or of an officer appointed under sub-section (1) of that section, or,
(b) a report under the hand of any Registered Medical Practitioner, in any hospital or dispensary maintained by the State Government or a local authority, or any other Registered Medical Practitioner authorised by the State Government in this behalf, in respect of any person examined by him or upon any matter or thing duly submitted to him for examination or analysis and report,
-may be used as evidence of the facts stated in such certificate, or as the case may be, report, in any proceedings, under this Act; but the Court may, if it thinks fit, and shall, on the application of the prosecution or the accused person, summon and examine any such person as to the subject-matter of his certificate or as the case may be, report.