The test is often suggested, as determining whether the relation of an illegal transaction is sufficiently close to the plaintiff's alleged cause of action to preclude recovery, that if enforcement of the plaintiff's claim does not require aid or proof of the illegal contract or transaction, the plaintiff may recover.31a As a negative test this seems sound; that is, a plaintiff cannot be allowed to recover if as part of his case he is compelled to allege and prove unlawful acts or agreements,32 but the converse does not seem equally true. Even though his case can be made out without indicating anything unlawful; proof must be admissible to show that the plaintiff is endeavoring to enforce an obligation which is part of, or so closely Consubsequently applied in many oases in the Supreme Court and in this court, namely, that when a contract is only remotely connected with an unlawful transaction, and rests upon a new and independent consideration, and the plaintiff can make out his case without any reliance upon the unlawful transaction, the new contract is valid and should be enforced. It will be observed from the statements of facts that the defendant here occupies the meanly dishonest position of having received the full purchase. price of plaintiff's goods, and then refusing to pay for them, although it has given repeated contracts upon new and independent considerations binding it to make the payment. As observed by Mr. Justice Holmes, when a member of the Supreme Court of Massachusetts, in Graves v. Johnson, 179 Mass. 53, 60 N. E. 383, 88 Am. St. Rep. 355, in fixing the degree of proximity to the illegal transaction necessary to taint a new contract, the moral turpitude involved in the original transaction will be given some weight by the court.

As the only moral turpitude here is that which is implied from failure to comply with a penal statute, there is no justification for an extension of the effect of the illegality to collateral undertakings resting upon a new consideration."

31 Mills Novelty Co. Dupouy, 203 Fed. 254,121 C. C. A. 452, 45 L. R. A. (N. S.) 788; Cleveland etc. Ry. Co. v. Hirsch, 204 Fed. 840, 123 C. C. A. 145; Scripps v. Sweeney, 160 Mich. 148, 125 N. W. 72; Ferguson v. Yunt, 13 S. Dak. 120, 82 N. W. 509; Johnson v. Berry, 20 S. Dak. 133,104 N. W. 1114,1L. R. A. (N. S.) 1159.

31a See oases cited in the preceding section.

32 Miller v. Ammon, 145 U. S. 421, 36 L. Ed. 759, 12 S. Ct. Rep. 884; Jemison v. Birmingham etc. R. Co., 125 Ala. 378, 28 So. 51; Western Union Tel. Co. v;. Yopst, 118 Ind. 248, 20 N. E. 222, 3 L. R. A. 224; Missouri Fidelity & Casualty Co. v. Scott (Okl.), 178 Pac. 122; Fitzgerald v. Grand Trunk R. Co., 63 Vt. 169, 22 Atl. 76, 13 L. R. A. 70 nefeted with an unlawful plan, as to make recovery opposed to public policy. "The line of proximity will vary somewhat according to the gravity of the evil apprehended." 33 Parol evidence is always competent to show that a written contract, though lawful on its face, was illegal or part of an illegal transaction; 34 and illegality if serious need not be pleaded or urged to enable the court to act upon it.35