Exclusion of probation: probation relief denied for convicted tax offenders while procedural defects won't invalidate tax proceedings. Two provisions: a probation exclusion denying application of probation statutes to persons convicted under the Income-tax Act except those under eighteen; and a substantive-validity rule that procedural instruments and proceedings under the Act are not invalid merely for mistakes, defects or omissions if they are, in substance and effect, in conformity with the intent and purpose of the Act.