Representative assessee trust condition: business profits under wills for dependent relatives taxed at maximum marginal rate if not exempt. The amendment confines the proviso to section 164(1) for business profits to trusts declared by will exclusively for a dependent relative and being the only such trust, and provides that any relevant income not exempt under the charitable/institutional exemption provisions shall be taxed at the maximum marginal rate, with corresponding provisos inserted into section 164(3) to ensure consistent application.