The question is whether the defendants were plagiarists of the plaintiff, Barry's, story. The theory is that Mackay saw it, and made it the basis of his play, which the defendants bought and used for one incident of their film. Several questions arise: (1) whether Mackay copied Barry's story at all; (2) if he did, whether the defendants are chargeable with his use of it; (3) if Mackay copied it, and they followed him, whether they took more than Barry's "idea", as contrasted with its expression. It has been held that one who copies from a plagiarist is himself necessarily a plagiarist, however innocent he may be (American Press Ass'n v. Daily Story Publishing Co., 7 Cir., 120 F. 766), but that would be a harsh result, and contrary to the general doctrine of torts. The wrong is copying; that is, using the author's work as a source. A copy of a copy does indeed do just that, but one is ordinarily liable for only those consequences of one's acts which a reasonable person would anticipate. Laying aside a possible action for unjust enrichment, or for an injunction after discovery, we should hesitate a long while before holding that the use of material, apparently in the public demesne, subjected the user to damages, unless something put him actually on notice. There is really nothing of that sort in this record, unless we count the fact that Mackay had sold his play first to Sainpolis, and afterwards to the defendants. That was not creditable, but it did not prove that Mackay stole it from some undisclosed third person. However, as we agree with the district judge that he has not been shown to have copied Barry's story at all, we shall leave the point for decision when it arises.
Aside from Hards's testimony there is no direct evidence that he did copy it; and the judge, who saw and heard Hards, did not believe him. After an interval of over eighteen years it was not unreasonable that he should be incredulous of Hards's recollection of Mackay's casual and trivial remark. There can be no doubt that the D'Estrampes story was current in