Yale law professor Ian Ayres works through Minneapolis & St. Louis Railway Co. v. Columbus Rolling-Mill, a classic contracts case on counter offers, as part of his American Contract Law course originally built for Coursera. He uses the case to show how a counter offer legally terminates the original offer, so that the offeree cannot later fall back on the initial terms once new terms have been proposed. The ten minute lecture is part of a section on the bargain relationship, tracing how courts read back and forth negotiation exchanges to decide when an offer is still open and when it has been extinguished. Ayres ties the doctrine to the practical stakes for buyers and sellers negotiating price and quantity, using the railway's shifting rail order as the running example.