I haven’t looked at this law, but suspect that especially since it was enacted 100 years ago, it only allows the chairman to review the return, not receive a copy.
Information on copy machines: Oct 23, 2013 - Inventor Chester Carlson used static electricity created with a handkerchief, light and dry powder to make the first copy on Oct. 22, 1938. The copier didn’t get on to the market until 1959, more than 20 years later. When it did, the Xerox machine prompted a dramatic change in the workplace.
Section f: Disclosure to Committees of Congress
Upon written request from the chairman of the Committee on Ways and Means of the House of Representatives, the chairman of the Committee on Finance of the Senate, or the chairman of the Joint Committee on Taxation, the Secretary shall furnish such committee with any return or return information specified in such request, except that any return or return information which can be associated with, or otherwise identify, directly or indirectly, a particular taxpayer shall be furnished to such committee only when sitting in closed executive session unless such taxpayer otherwise consents in writing to such disclosure.
Any committee described in paragraph (1) or the Chief of Staff of the Joint Committee on Taxation shall have the authority, acting directly, or by or through such examiners or agents as the chairman of such committee or such chief of staff may designate or appoint, to inspect returns and return information at such time and in such manner as may be determined by such chairman or chief of staff. Any return or return information obtained by or on behalf of such committee pursuant to the provisions of this subsection may be submitted by the committee to the Senate or the House of Representatives, or to both. The Joint Committee on Taxation may also submit such return or return information to any other committee described in paragraph (1), except that any return or return information which can be associated with, or otherwise identify, directly or indirectly, a particular taxpayer shall be furnished to such committee only when sitting in closed executive session unless such taxpayer otherwise consents in writing to such disclosure.