In any proceeding for the enforcement of a claim for compensation under this chapter, it shall be presumed in the absence of substantial evidence to the contrary 1. That the claim comes within the provision of this chapter;
That sufficient notice thereof was given;
That the injury was not occasioned by the willful intention of the injured employee to bring about the injury or death of himself or of another;
That the injury did not result solely from the intoxication of the injured employee while on duty.
That the contents of medical and surgical reports introduced in evidence by claimants for compensation shall constitute prima facie evidence of fact as to the matter contained therein.