An Act amending the act of March 4, 1971 (P.L.6, No.2), known as the Tax Reform Code of 1971, repealing provisions relating to discounts; further providing for the definition of "taxable" and taxable year"; providing for the definitions of "commonly controlled group" and "separate company"; further providing for imposition of tax, for reports and payment of tax and for consolidated reports; providing for provisions relating to the taxation of tobacco products; imposing a tax on the extraction of natural gas; providing for natural gas severance registration certificate, for duties of the Department of Revenue, for tax assessments and tax liens; imposing penalties; providing for service of process, for rulemaking, for cooperation with other governments and for bonds; further providing for underpayment of estimated tax; imposing penalties; and making an appropriation.