Joint and several liability preserves partners' responsibility for firm tax, interest and penalties despite dissolution or reconstitution. Liability for unpaid tax, interest and penalty continues when a firm, association of persons or HUF discontinues, dissolves, partitions or is reconstituted. Every partner or member in office at the time of such change is jointly and severally liable for amounts determined or imposed before or after the change, and the Act's provisions apply so far as may be to treat those persons as taxable persons for recovery.