Subject to the provisions of this Act, a court-martial may, on convicting a person subject to this Act of any of the offences specified in sections 34 to 68 inclusive, award either the particular punishment with which the offence is stated in the said sections to be punishable, or, in lieu thereof, any one of the punishments lower in the scale set out in section 71, regard being had to the nature and degree of the offence.