The Commission's inquisitorial powers are not without limit. Int. Com. Comm. v. Brimson, 154 U. S. 447, 473.

Section 20 as amended by the Hepburn Act does not give the Commission access to the correspondence of the carrier. Connecticut Life Ins. Co. v. Schaefer, 94 U. S. 459; Blackburn v. Crawfords, 3 Wall. 175; 4 Wigmore on Evid., § 2290, p. 3193.

The rule of noscitur a sociis applies to the construction of this statute. Virginia v. Tennessee, 148 U. S. 503. Penal statutes should be strictly construed. United States v. Wiltberger, 5 Wheat. 96.

Statutes should be construed, if possible, to avoid reasonable doubts as to constitutionality. Harriman v. Int. Com. Comm., 211 U. S. 422.

The Hepburn Amendment to § 20 of the Commerce Act does not give the Commission access to records existing prior to the passage of that Act.

The search of defendant's papers sought by the Commission's examiners would, if permitted, be an unreasonable search, contrary to the Federal Constitution; to the protection of which amendment corporations are entitled. Hale v. Henkel, 201 U. S. 43, 75; In re Pacific Ry. Comm., 32 Fed. Rep. 241, 263.

MR. JUSTICE DAY delivered the opinion of the court.

This is an appeal from and writ of error to the District Court of the United States for the Western District of Kentucky, refusing a writ of mandamus which the United States undertook to obtain under authority of § 20 of the Act to Regulate Commerce, as amended, June 29, 1906, c. 3591, 34 Stat. 584, 594, 595. In view of the character of an action in mandamus we are of opinion that the review is by writ of error. Ins. Co. v. Wheelwright, 7 Wheat. 534; Commonwealth of Kentucky v. Dennison, 24 How. 66, 97;

High on Extraordinary Legal Remedies, §§ 6, 557. The appeal is therefore dismissed.

The petition sets forth the authority conferred upon the Commission by § 20 of the Act, and also § 12, and embodies a copy of a resolution passed by the Senate of the United States which is given in the margin.' It further

1 "RESOLUTION.

"Resolved, That the Interstate Commerce Commission be, and the same is hereby, directed to investigate, taking proof and employing counsel if necessary, and report to the Senate as soon as practicable

"First. What amount of stock, bonds, and other securities of the Nashville, Chattanooga and Saint Louis Railway is owned or controlled by the Louisville and Nashville Railroad;

"Second. What other railroad or railroads in the territory served by the Louisville and Nashville Railroad and the Nashville, Chattanooga and Saint Louis Railway have been purchased, leased, controlled, or arrangements entered into with, for the purpose of controlling by either the Louisville and Nashville Railroad or the Nashville, Chattanooga & Saint Louis Railway;

"Third. Whether the Louisville and Nashville Railroad and the Nashville, Chattanooga and Saint Louis Railway serve the same territory in whole or in part, and whether, under separate ownership, they would be competitive to the various points in their territories;

"Fourth. Any other fact or facts showing or tending to show the further relations between the Louisville and Nashville Railroad and the Nashville, Chattanooga and Saint Louis Railway, and any fact or facts showing or tending to show whether these relations restrict competition and maintain fixed rates;

'Fifth. The terms of the lease of the Nashville and Decatur Railroad by the Louisville and Nashville Railroad, and what amount, if any, of stock, bonds, and other securities of the Nashville and Decatur Railroad, and of the Lewisburg and Northern Railroad are owned by the Louisville and Nashville Railroad, or any of its subsidiaries, or holding companies;

"Sixth. Whether the Nashville and Decatur Railroad, the Lewisburg and Northern Railroad, and the Louisville and Nashville Railroad serve the same territory, in whole or in part, and whether, under separate ownership, these railroads would be competitive between various points in their territories;

"Seventh. Any other fact or facts showing or tending to show, the

states that for the purpose of enabling the Commission to perform its duties, it appointed two special agents and duly authorized them to inspect and examine the accounts, records and memoranda of the defendant Railway Company; that on February 4, 1914, one of said agents demanded of the Vice President of the defendant, the officer

further relations between the Louisville and Nashville Railroad, the Nashville and Decatur Railroad, and the Lewisburg and Northern Railroad, and any fact or facts showing, or tending to show, whether these relations restrict competition and maintain and fix rates;

"Eighth. Any fact or facts showing, or tending to show (a) the relations between the Louisville and Nashville Railroad, the Nashville, Chattanooga and Saint Louis Railway, the Tennessee Midland Railroad, the Tennessee, Paducah and Alabama Railroad, and any other railroads that have been purchased or leased by either or both of said railroad companies, and whether such relations restrict competition and maintain and fix rates; and, (b) whether the lease of the Western and Atlantic Railroad by the Nashville, Chattanooga and Saint Louis Railway from the State of Georgia, and the arrangement made between the Louisville and Nashville and the Nashville, Chattanooga, and Saint Louis Railway by which the former uses the tracks of the said Western and Atlantic Railway restrict competition, restrain trade, and determine and fix rates;

"Ninth. Any fact or facts showing, or tending to show, whether the ownership of the Louisville and Nashville Railroad and the Nashville, Chattanooga and Saint Louis Railway of any railroad terminals or terminal companies, steamboats and steamboat lines upon the Cumberland and Tennessee Rivers, and any dock or dock yards at Pensacola, New Orleans, Mobile, or other seaport establishes a monopoly and restricts competition and determines and fixes rates;

"Tenth. Any fact or facts showing, or tending to show, whether an agreement or arrangement has been entered into between the Louisville and Nashville and other railroad companies for the purpose of preventing competition from entering into any of the territory served by the Louisville and Nashville Railroad, in consideration of the Louisville and Nashville Railroad agreeing not to enter into certain other territory, or in consideration of any other agreement or arrangement;

"Eleventh. What amount of stock, if any, the Atlantic Coast Line Company or Atlantic Coast Holding Company owns in the Louisville and Nashville Railroad, and in the Atlantic Coast Line, and whether

Opinion of the Court.

236 U. S. in charge and control of the accounts, records and memoranda of the Company, and to and of other officers, access to and opportunity to examine the accounts, records and memoranda kept by the defendant prior to August 28, 1906, [The Hepburn Act took effect August 29, 1906] and that the same was refused by the officers of the Company; that on February 4, 1914, a demand was made for an opportunity to examine the accounts, records and memoranda of the defendant on and subsequent to August 28, 1906, which was refused; and a writ of mandamus was asked against the company, requiring it to give access to its accounts, records and memoranda, and its correspondence and copies of correspondence, and indexes thereto, and to afford opportunity to examine the same to the Commission and its agents and examiners, and to give such access to and opportunity to examine the said accounts, records and memoranda made and kept by and for said

the ownership by such holding company of a majority of stock in both of the aforesaid railroads tends to restrict competition and maintain and fix rates;

"Twelfth. What amount, if any, the Louisville and Nashville Railroad, the Nashville, Chattanooga and Saint Louis Railway, the Nashville and Decatur Railroad, and the Lewisburg and Northern Railroad, all or any of them, have subscribed, expended or contributed for the purpose of preventing other railroads from entering any of the territory served by any of these railroads for maintaining political or legislative agents, for contributing to political campaigns, for creating sentiment in favor of any of the plans of any of said railroads; and,

"Thirteenth. (a) The number of free annual passes; (b) the number of free-trip passes; (c) the number of every kind of free passes issued by each of said railroads each year since January first, nineteen hundred and eleven, to members of legislative bodies and other public officials, or at the request of members of legislative bodies and other public officials; (d) the total mileage traveled upon free passes issued under each of the above classifications; and (e) the amount in money the free passes issued under each of the above-mentioned classifications would equal at the regular rates for such service of each of the above-named railroads."

defendant both before, on, and subsequent to August 28, 1906, including correspondence, copies of correspondence, and indexes thereto, and other indexes to said accounts, records, and memoranda.

To this petition the defendant answered, setting out that it did, prior to the beginning of the suit, give the examiners access to the correspondence other than privileged communications, and that after this suit it did refuse and does now refuse to give to said Commission or to said agent access to or opportunity to examine correspondence received by it before, on, or subsequent to August 28, 1906, or copies of correspondence sent out by defendant before, on or subsequent to that date, or the indexes kept with respect to said outgoing and incoming correspondence by defendant (except correspondence as to passes issued since January 1, 1911), and the defendant set up that its correspondence contains private communications between its various officers and agents regarding various matters which did not in any way pertain to the provisions of the Act to Regulate Commerce, nor to any act of Congress, the provisions of which it is made the duty of the Interstate Commerce Commission to enforce, and avers that said correspondence contains communications of a private and confidential nature between the president of the railway company and the heads of the various departments, relative to its internal affairs, to its proposed constructions and extensions in the future, to its policies with competing and rival roads, to its relations with labor organizations represented in its operating department, and to a variety. of other subjects of a private and confidential nature, and that do not relate to the provisions of the Act to Regulate Commerce and acts amendatory thereto, or to any other act of Congress as to the enforcement of which any duty has been imposed upon the Interstate Commerce Commission, and that said correspondence also contains confidential, private, and privileged communications be