In September 1855, Lincoln and Koerner were associated in litigating Clark & Morrison v. Page et al., a bill in chancery lawsuit in the Macoupin County Circuit Court. Bill in Chancery is a generic term for any action in the chancery division of the law. The chancery or equity division is devoted to settling legal issues where there is no remedy in the common law.

In the case, Henry A. Clark and James L. D. Morrison, stockholders in the Ohio and Mississippi Railroad Company, accused Henry D. Bacon and Joshua H. Alexander, leading officers of the St. Louis banking house of Page and Bacon, and others of making fraudulent deals in taking over contractors’ interest in building the railroad. Bacon, who was also the president of the railroad’s board, had submitted a bill for $1,158,484.61 as a representative of Page and Bacon in June 1855. The same month, the railroad gave Bacon a promissory note and a deed of trust as collateral. When the railroad failed to pay the bill, Alexander, who was also the treasurer of the railroad, took possession of the railroad and promptly advertised for its sale in order to collect the funds owed. In August 1855, Clark and Morrison filed a bill in chancery in the St. Clair County Circuit Court for a receiver to manage the railroad’s affairs, for an injunction to stop Alexander from selling the railroad, and for a cancellation of the $1.1 million promissory note and deed of trust.

In August 1855, the court granted a change of venue to the Macoupin County Circuit Court because Sidney Breese, the judge in St. Clair County, was a named defendant in the case. Bacon, Alexander, and the other defendants retained Lincoln, William H. Holmes, John M. Palmer, Lewis B. Parsons, Jr., and William H. Underwood. Clark and Morrison retained Koerner, William N. Grover, Britton Hill, and Lyman Trumbull. Lincoln argued that the railroad company, rather than the stockholders, was the proper plaintiff. "Notes of Argument in Law Case" were a part of Lincoln’s oral argument in this case. Ultimately, after several years of continuances, in December 1859 the court ruled that Bacon and Alexander’s conflict of interest voided the promissory note and deed of trust.

No other correspondence between Lincoln and Koerner about this case has been located. However, on July 19, 1857, Lincoln wrote Koerner a letter about a separate federal case in which Lincoln secured a favorable settlement for Bacon. For more information about this federal case, see Bacon v. Ohio & Mississippi RR, Martha L. Benner and Cullom Davis et al., eds., The Law Practice of Abraham Lincoln: Complete Documentary Edition, 2d edition (Springfield: Illinois Historic Preservation Agency, 2009), http://www.lawpracticeofabrahamlincoln.org/Details.aspx?case=137508.