## Facts

- A patentee held a reissued patent for a leather-treatment improvement containing two distinct claims: (1) use of “fat liquor” generally in treating leather, and (2) a specific process for treating bark-tanned lamb or sheep skin using a compound applied in a particular manner.
- The patentee previously sued the same defendants at law for infringement and obtained a general jury verdict and damages judgment.
- In the prior action, the pleadings and verdict did not specify whether infringement and recovery rested on the first claim, the second claim, or both.
- The patentee later filed a separate equity suit against the same defendants seeking an injunction and an accounting for continued infringement.
- In the equity suit, defendants challenged novelty, prior public use, and whether the reissue (to the extent changed) covered the same invention as the original.
- The patentee argued the prior damages judgment conclusively established patent validity and estopped defendants from raising invalidity-related defenses.
- No competent extrinsic evidence was introduced to clarify what claim(s) or issues the jury necessarily decided in the prior case.

## Issues

1. Whether a prior damages judgment for infringement of a multi-claim patent precludes the same defendants in a later suit from contesting patent validity when the record does not show which claim(s) formed the basis of the verdict.
2. Whether, and on what showing, an ambiguous prior record can support issue preclusion.

## Decision

- The Supreme Court affirmed the decree for defendants.
- A prior judgment is conclusive only as to issues actually litigated and necessarily decided.
- If the record leaves uncertain what precise issue was determined, there is no estoppel unless the uncertainty is removed by competent extrinsic evidence.
- Because the prior record did not show whether liability and recovery rested on the first claim, the second claim, or both, the prior judgment did not bar defendants from litigating validity defenses in the equity suit.

## Legal Principles

- Issue preclusion applies only to questions “actually and necessarily decided” in the prior action.
- The precise issue determined must appear on the face of the prior record or be established by competent extrinsic evidence.
- If the record leaves the necessary basis of decision to conjecture, the judgment is not conclusive when pleaded as an estoppel.
- For patents with multiple claims, a judgment based on one claim does not necessarily determine the validity of other claims; a patent may be valid in part and invalid in part.
- Extrinsic evidence may be used to identify the precise point previously decided when the record itself is unclear.

## Conclusion

Because the earlier infringement verdict and record did not identify which patent claim supported the recovery and no extrinsic proof cured that ambiguity, the earlier judgment did not preclude defendants from contesting patent validity in the later equity suit.


Russell v. Place, 94 U.S. 606 (1876)