is or may be bound by a judgment in the action; or (3) when the applicant is so situated as to be adversely affected by a distribution or other disposition of property in the custody of the court or of an officer thereof.

(b) PERMISSIVE INTERVENTION. Upon timely application anyone may be permitted to intervene in an action: (1) when a statute of the United States confers a conditional right to intervene; or (2) when an applicant's claim or defense and the main action have a question of law or fact in common. In exercising its discretion the court shall consider whether the intervention will unduly delay or prejudice the adjudication of the rights of the original parties.

(c) PROCEDURE. A person desiring to intervene shall serve a motion to intervene upon all parties affected thereby. The motion shall state the grounds therefor and shall be accompanied by a pleading setting forth the claim or defense for which intervention is sought. The same procedure shall be followed when a statute of the United States gives a right to intervene. When the constitutionality of an act of Congress affecting the public interest is drawn in question in any action to which the United States or an officer, agency, or employee thereof is not a party, the court shall notify the Attorney General of the United States as provided in the Act of August 24, 1937, c. 754, §1.

Rule 25. Substitution of Parties.

(a) DEATH.

(1) If a party dies and the claim is not thereby extinguished, the court within 2 years after the death may order substitution of the proper parties. If substitution is not so made, the action shall be dismissed as to the deceased party. The motion for substitution may be made by

V. DEPOSITIONS AND DISCOVERY

Rule 26. Depositions Pending Action.

(a) WHEN DEPOSITIONS MAY BE TAKEN. By leave of court after jurisdiction has been obtained over any defendant or over property which is the subject of the action or without such leave after an answer has been served, the testimony of any person, whether a party or not, may be taken at the instance of any party by deposition upon oral examination or written interrogatories for the purpose of discovery or for use as evidence in the action or for both purposes. The attendance of witnesses may be compelled by the use of subpoena as provided in Rule 45. Depositions shall be taken only in accordance with these rules. The deposition of a person confined in prison may be taken only by leave of court on such terms as the court prescribes.

(b) SCOPE OF EXAMINATION. Unless otherwise ordered by the court as provided by Rule 30 (b) or (d), the deponent may be examined regarding any matter, not privileged, which is relevant to the subject matter involved in the pending action, whether relating to the claim or defense of the examining party or to the claim or defense of any other party, including the existence, description, nature, custody, condition, and location of any books, documents, or other tangible things and the identity and location of persons having knowledge of relevant facts.

(c) EXAMINATION AND CROSS-EXAMINATION. Examination and cross-examination of deponents may proceed as permitted at the trial under the provisions of Rule 43 (b).

(d) USE OF DEPOSITIONS. At the trial or upon the hearing of a motion or an interlocutory proceeding, any part or all of a deposition, so far as admissible under the rules of evidence, may be used against any party who was present or represented at the taking of the deposition or who had due notice thereof, in accordance with any one of the following provisions:

(1) Any deposition may be used by any party for the purpose of contradicting or impeaching the testimony of deponent as a witness.

(2) The deposition of a party or of any one who at the time of taking the deposition was an officer, director, or managing agent of a public or private corporation, partnership, or association which is a party may be used by an adverse party for any purpose.

(3) The deposition of a witness, whether or not a party, may be used by any party for any purpose if the court finds: 1, that the witness is dead; or 2, that the witness is at a greater distance than 100 miles from the place of trial or hearing, or is out of the United States, unless it appears that the absence of the witness was procured by the party offering the deposition; or 3, that the witness is unable to attend or testify because of age, sickness, infirmity, or imprisonment; or 4, that the party offering the deposition has been unable to procure the attendance of the witness by subpoena; or 5, upon application and notice, that such exceptional circumstances exist as to make it desirable, in the interest of justice and with due regard to the importance of presenting the testimony of witnesses orally in open court, to allow the deposition to be used.

(4) If only part of a deposition is offered in evidence by a party, an adverse party may require him to introduce all of it which is relevant to the part introduced, and any party may introduce any other parts.

Substitution of parties does not affect the right to use depositions previously taken; and, when an action in any court of the United States or of any state has been dismissed and another action involving the same subject matter is afterward brought between the same parties or their representatives or successors in interest, all depositions lawfully taken and duly filed in the former action may be used in the latter as if orginally taken therefor.

(e) OBJECTIONS TO ADMISSIBILITY. Subject to the provisions of Rule 32 (c), objection may be made at the trial or hearing to receiving in evidence any deposition or part thereof for any reason which would require the exclusion of the evidence if the witness were then present and testifying.

(f) EFFECT OF TAKING OR USING DEPOSITIONS. A party shall not be deemed to make a person his own witness for any purpose by taking his deposition. The introduction in evidence of the deposition or any part thereof for any purpose other than that of contradicting or impeaching the deponent makes the deponent the witness of the party introducing the deposition, but this shall not apply to the use by an adverse party of a deposition as described in paragraph (2) of subdivision (d) of this rule. At the trial or hearing any party may rebut any relevant evidence contained in a deposition whether introduced by him or by any other party.

Rule 27. Depositions Before Action or Pending Appeal.

(a) BEFORE ACTION.

(1) Petition. A person who desires to perpetuate his own testimony or that of another person regarding any matter that may be cognizable in any court of the United States may file a verified petition in the district court of the United States in the district of the residence of any expected adverse party. The petition shall be entitled in the name of the petitioner and shall show: 1, that the petitioner expects to be a party to an action cognizable in a court of the United States but is presently unable to bring it or cause it to be brought, 2, the subject matter of the expected action and his interest therein, 3, the facts which he desires to establish by the proposed testimony and his reasons for desiring to perpetuate it, 4, the names or a description of the persons he expects will be adverse parties and their addresses so far as known, and 5, the names and addresses of the persons to be examined and the substance of the testimony which he expects to elicit from each, and shall ask for an order authorizing the petitioner to take the depositions of the persons to be examined named in the petition, for the purpose of perpetuating their testimony.

(2) Notice and Service. The petitioner shall thereafter serve a notice upon each person named in the petition as an expected adverse party, together with a copy of the petition, stating that the petitioner will apply to the court, at a time and place named therein, for the order described in the petition. At least 20 days before the