1. This is an appeal by the added defendants in a suit for arrears of rent.

2. The plaintiff instituted the suit on the 16th April, 1919, against the tenant-defendant for recovery of rent for the period between the 18th October, 1916, and the 13th April, 1919. His allegation was that the tenant held under him an area of one kani seven gandas of land at an annual rent of Rs. 43-11.6. The defendant filed his written statement on the 17th July, 1919, and urged, amongst; other pleas, that the plaintiff alone was not competent to maintain the suit as he was in effect a fractional landlord. The Court thereupon adjourned the case till the 7th August, 1919. On the date, the plaintiff applied for time to add certain persons as defendants. The adjournment was granted, and on the 28th October, 1919, at the instance of the plaintiff, the present appellants were added as defendants. The plaint, however, was not amended as contemplated by Order 1, Rule 10, Sub-rule (4) of the Code of Civil Procedure, and as it now stands it does not disclose a cause of action against the added defendants. Notice was served upon the added defendants who entered appearance, and on the 16th January, 1920 filed their written statement. They denied that the plaintiff had any cause of action against them for the arrears claimed, and asserted that they were his co-sharers. They further repudiated the transaction which, it was alleged, had taken place between the plaintiff and their predecessor-in-interest. On these pleadings, no issues were framed. The Court proceeded to try the suit as between the plaintiff on the one hand and the defendants on the other, and, on the 23rd February, 1920, pronounced judgment in favour of the plaintiff to the extent of one-half of the claim.

3. The trial Court came to the conclusion that the plaintiff had established his title only to a half share of the property in dispute and that the other half share was held by the added defendants who were described as pro forma defendants, that is, defendants against whom no relief was claimed. The plaintiff was dissatisfied with this decision and appealed to the Subordinate Judge.

4. The lower Appellate Court then proceeded to receive additional evidence in the shape of petitions of compromise, dated the 11th April, 1918, which had formed the foundation of consent decree, dated the 22nd April, 1919, in a previous litigation between the parties instituted on the 19th April 1917; these petitions of compromise were deemed essential for the elucidation of the terms of the consent decree. The Subordinate Judge ultimately allowed the appeal and decreed the claim in full. He came to the conclusion that the transactions between the plaintiff and the added defendants, which were impeached by the latter, must be treated as operative till they had been cancelled in a suit properly framed for that purpose. The added defendants have now appealed to this Court and have contested the propriety of the decision of the Subordinate Judge principally upon two grounds, namely, first, that they were entitled to impeach the validity of the transactions whereon the plaintiff relied by way of defence without recourse to a regular suit; and secondly, that the transactions were manifestly inoperative as against the infants concerned, who were, but could not, under the Mohamedan law, be validly represented by their mother as their guardian. We are of opinion that the decree made by the Subordinate Judge cannot be supported.

5. It is plain that the effect of the addition of the appellants as defendants has been to transform a simple rent suit into a complex title suit. This course was rightly condemned by Field, J., in the case of Lodai Mollah v. Kallay Dass Roy (1881) 8 Cal. 238. To guard against possible misapprehension, we must state at the outset that it cannot be affirmed as a broad proposition of law that a question of title may not be incidentally investigated in a suit for arrears of rent. "Where the tenant defendant disputes the extent of the title of the plaintiff to the arrears demanded, it is incumbent on the Court to determine the point before the claim is allowed or disallowed. This view is supported by the decision in Rahimannessa Bibi v. Mahadeb Das Mal (1910) 12 C.L.J. 428. But subject to this reservation, parties should not be added in a suit for rent so as to alter its nature and scope and to transform it into a suit for determination of a complicated question of title to land.

6. We are further of opinion that the Subordinate Judge fell into a manifest error, when he held that the added defendants ware not competent to assail in their defence the validity of the transactions whereon the plaintiff relied. The plaintiff was admittedly the original owner of the land in suit. His case is that on the 7th February, 1906, he transferred one-half of his interest in the property to the predecessors-in-interest of the added defendants. The true nature of his transaction is in controversy. The plaintiff maintains that the transfer was a mortgage in the disguise of a conveyance. The defendants maintain that the transaction was in essence as in form an out-and-out sale. Apart from this, the plaintiff maintains that the mortgage has been repaid and that on the 7th and 11th January, 1918, he obtained from the defendants two deeds of release which recite that the mortgage has been satisfied so as to re-vest the full title in himself.

7. The defendants urge that inasmuch as the original transfer was by way of a conveyance, the title could not be re-vested in the plaintiff by a deed of release and that a reconveyance was the only effective means for a re-transfer of the title, as ruled in Oodey Koodwar v. Ladoo (1870) 13 M.I.A. 585, Jadunath v. Ruplal (1906) 33 Cal. 967, Dharam Chand v. Manji Sahu (19l2)16 C.L.J. 436, Narak Lal v. Thago Lal (1911) 22 C.L.J. 380 and Mathuramohan v. Ram Kumar (1915) 43 Cal. 790.

8. The defendants further maintain that the deeds of release, in so far as they were executed by the mother of the infants concerned as their guardian, are not valid, because, as pointed out by the Judicial Committee in Imam Bandi v. Mutsuddi A.I.R. 1918 P.C. 11 and Matadin v. Ahmadalli (1912) 34 All. 213, the mother was not in the eye of law clothed with authority as de facto guardian to transfer the interest of the infants. It is with regard to this question that the Subordinate Judge has held that the added defendants could impeach the validity of the deeds of release only in a separate suit specially framed for that purpose. His view is opposed to the decision in Dwijendra Mohan v. Manorama A.I.R. 1922 Cal. 150, which applied the rule enunciated in Eastern Mortgage and Agency Co. v. Bevati Ray (1906) 3 C.L.J. 260, Hem Chandra v. Lalit Mohan (1912) 16 C.W.N. 715 and Mansharam v. Ahmed (1916) 21 C.W.N. 63. It is an elementary proposition that if the plaintiff relies upon a transaction in support of his title, the defendant is entitled to impeach its validity by way of defence to the claim and is not bound to have recourse to a separate suit for that purpose. This renders obvious the impropriety of the addition of the defendants as parties to this litigation. The deeds of release affect not merely the property whereof the rent is in dispute in this suit, but other properties as well, so that if they are set aside, other transactions will be reopened and possibly an order for restitution on equitable terms required. It would not be right and proper to investigate questions of this description in a suit instituted ostensibly for the recovery of arrears of rent alleged to be due to the plaintiff from the tenant-defendant.

9. There is thus no escape from the conclusion that the added defendants should not have been brought on the record under Order 1, Rule 10, Sub-rule (2) of the Code of Civil Procedure. That sub-rule provides that the Court may, at any stage of the proceeding, either upon or without the application of either party, and on such terms as may appear to the Court to be just, order that the name of any person who ought to have been joined, whether as plaintiff or defendant, or whose presence before the Court may be necessary in order to enable the Court effectually and completely to adjudicate upon and settle all the questions involved in the suit, be added. This provision confers a discretion upon the Court, and that discretion must be exercised in view of the special circumstances of the particular litigation, subject, however, to the general rule that parties cannot be added so as to alter the nature of the suit: Oh Ling Tee v. Awkinifee (1868) 10 W.R. 86 and Hingu Lal v. Baldeo Ram (1902) 24 All. 553. It is further plain that a, person may be added as a party to a suit only in two cases, first, when he ought to have been joined and has not been so joined, or, secondly, when without his presence the question in the suit cannot be completely decided: Mc. Cheane v. Gyles (1902) 1 Ch. 911 and Moser v. Marsden (1892) 1 Ch. 487. In this connexion reference may be made to the decisions in Kisan Prasad v. Harnarayan (1911) 38 All. 272, Guruvayya v. Dattatraya (1903) 28 Bom. 11 and Shahasheb v. Sadashiv Supdi (1918) 43 Bom. 575 which illustrate the distinction between a proper party and a necessary party. In the case before us, the added. defendants were neither proper party and a necessary parties. The plaint as framed did not disclose a cause of action against them. There was no allegation that they had prior to the suit set up a claim to realize rent from the tenant defendant, much less that they had actually intercepted the rent payable by him.

10. We are accordingly of opinion that these defendants should not have been added as parties to the suit; the consequence of their presence has in fact been to convert a simple suit, for rent into complicated title suit, involving numerous questions of law and fact, such as-Was the original transfer a mortgage or a sale. Was a re-conveyance necessary to revest title in the original owner? Could a release operate as a reconveyance? Could a Mahomedan mother act as de facto guardian and validly alienate the estate of her children and could a release by her be set aside except on equitable terms?

11. The result is that this appeal is allowed and the decree of the Subordinate Judge set aside. The added defendants will be discharged from the suit and their names will be removed from the record. The case will be remanded to the Court of first instance to be tried as a suit 'for rent between the original plaintiff and the original defendant. In order to determine whether the plaintiff is entitled to the entire rent or only a share thereof, the Court will investigate incidentally the extent of the title of the plaintiff in the* land, and how far he has been in actual enjoyment of his right in the immediately preceding years. We are constrained to remand the case to the Court of first instance, because, after the added defendants were brought on the record, the original defendant ceased to take an interest in the controversy, it was to him immaterial whether the rent in arrear was decreed in favour of the plaintiff alone or in favour of the plaintiff jointly with the added defendants. Now that the added defendants have been removed from the record, the original defendant must be allowed an opportunity to contest) the claim of the plaintiff. Each party will bear his own costs in all the Courts up to this stage.