JAGADISAN, J.

These tax revision cases and the writ petitions raise a common question of law, challenging the validity of the amendment to section 8-B(2) of the Madras General Sales Tax Act introduced by Madras Act 1 of 1957. It will be convenient to deal with this point first before setting out the facts of each case and considering the contentions turning upon them.

Section 8-B, as it stood before its amendment by Madras Act I of 1957, reads :-

"8-B. (1) No person who is not a registered dealer shall collect any amount by way of tax under this Act; nor shall a registered dealer make any such collection except in accordance with such conditions and restrictions, if any, as may be prescribed :

Provided that the State Government may exempt persons who are not registered dealers from the provisions of this sub-section until such date, not being later than the 1st day of April, 1948, as the State Government may direct.

(2) Every person who has collected or collects any amount by way of tax under this Act, on or after the 1st day of April, 1947, shall pay over to the State Government within such time and in such manner as may be prescribed, all amounts so collected by him if the