In prosecutions under section 48, it shall be presumed, until the contrary is proved, that the accused person has committed an offence under that section in respect of any liquor or intoxicating drug, or any still, utensil, implement, or apparatus whatsoever for the manufacture of liquor, or any intoxicating drug, or any such materials as are ordinarily used in the manufacture of liquor, or any intoxicating drug, for the possession of which he is unable to account satisfactorily; and the holder of a licence or permit under this Act shall be punishable, as well as the actual offender, for any offence committed by any person in his employ and acting on his behalf under any of the previous sections of this Act as if he had himself committed the same, unless he shall establish that all due and reasonable precautions were exercised by him to prevent the commission of such offence :
Provided that no person, other than the actual offender, shall be punished with imprisonment except in default of payment of fine.