Mrs. Alexander's Cotton was a case heard by the United States Supreme Court in 1864. The case involved Mrs. Mary Ann Alexander, who had been arrested and fined for selling cotton without paying taxes on it as required by federal law. She argued that she should not be held liable for the tax because her husband owned the cotton before his death and that he had already paid all necessary taxes on it prior to his passing away. The court ruled against Mrs. Alexander, finding that although her husband may have paid any applicable taxes at one point, those payments were no longer valid after his death since they did not apply to her ownership of the property or its sale after his demise; thus, she was responsible for paying any applicable taxes due from such sales herself regardless of whether or not they had previously been paid by someone else in relation to this same property during their lifetime..

In Mrs. Alexander's Cotton, the Supreme Court was asked to decide whether a slave owner could recover damages for cotton that had been destroyed by Union forces during the Civil War. The majority opinion held that since slavery was illegal and unconstitutional at the time of destruction, no recovery could be allowed. However, in his dissenting opinion Justice Field argued that although slavery may have been illegal when the cotton was destroyed, it had not yet been declared so by any court or legislative body at the time of its destruction and therefore should still be considered valid property under existing law. He further argued that if slaves were considered property then their labor-produced products such as cotton should also be treated as such regardless of any later legal developments regarding slavery itself. Thus he concluded that Mrs Alexander should receive compensation for her lost property even though it had been produced through slave labor prior to emancipation being declared constitutional law.