Fisher v. Perkins was a United States Supreme Court case that dealt with the issue of whether a state could be held liable for the negligence of its agents. The case involved a dispute between a railroad company and a passenger, who was injured while riding on the company's train. The passenger, Fisher, sued the railroad company for damages, claiming that the company had been negligent in its operation of the train. The railroad company argued that it could not be held liable for the negligence of its agents, as it was a state-owned entity. The Supreme Court ultimately held that the state could be held liable for the negligence of its agents. The Court reasoned that the state had a duty to ensure the safety of its citizens, and that this duty extended to the operation of its trains. The Court also noted that the state had a duty to ensure that its agents acted in a reasonable manner, and that the state could be held liable for any negligence on the part of its agents. In the end, the Supreme Court held that the state could be held liable for the negligence of its agents, and that the railroad company was liable for the damages suffered by Fisher. This case established the principle that states can be held liable for the negligence of their agents, and that they must take reasonable steps to ensure the safety of their citizens.

In Fisher v. Perkins, the Supreme Court was tasked with determining whether a contract between two parties should be enforced in regards to an agreement for payment of legal fees. The majority opinion held that the contract should not be enforced because it lacked consideration and was therefore unenforceable under Virginia law. In his dissenting opinion, Justice Field argued that although there may have been no formal consideration given by either party at the time of making the agreement, subsequent events had provided sufficient consideration to make it enforceable. He noted that when one party performs services as agreed upon in a contract and is then denied compensation due to lack of formal consideration at its inception, this constitutes unjust enrichment on behalf of those who benefit from such services without paying for them. Therefore he concluded that even though there may have been no initial exchange or promise made by both parties when entering into their agreement, later performance constituted valid consideration which rendered their contract enforceable under Virginia law.