If you have a citation for a historical statute, the simplest way to pull it is to use an online source for Statutes at Large or public laws. Try HeinOnline's Statutes at Large Library.
Online Sources
VitalLaw: Federal Tax - Under the "Archives" box, select the year you want to research in the menu. From there, you can view the tax code as it existed in the specified year.
RIA Checkpoint: Archives - Under the "Table of Contents" tab, navigate to "Checkpoint Archives." Here you can access the Internal Revenue Code, as well as Explanations and Annotations, from 1990 forward. Also included are Internal Revenue Code of 1939 and Internal Revenue Code of 1954.
HeinOnline: Standard Federal Tax Reporter - Contains a comprehensive collection of federal income tax information, such as full text of all proposed, temporary and final federal income tax law regulations, as well as full text of federal administrative rulings and documents. Coverage is from inception through 1985.
IRS: Internal Revenue Bulletin - The Internal Revenue Bulletin & Cumulative Bulletin often reprint significant tax laws.