The partnership of McCamey, Sheerin & Dumas (MS&D) entered into a contract with Western Oil Sales Corporation (Western Oil) (defendant) pursuant to which MS&D agreed to sell and deliver crude oil to Western Oil in exchange for certain acts and payments by Western Oil. The contract provided that it was binding upon the parties’ successors and assigns but did not otherwise refer to assignment or transfers. After three months of oil deliveries, Western Oil assigned its rights and obligations under the contract to the American Oil Company. Western Oil notified MS&D of the assignment, demanded that MS&D make future deliveries to American Oil, and disclaimed any further liability to MS&D under the contract. MS&D refused to deliver oil to American Oil and considered the contract with Western Oil terminated. In connection with a sale of its oil leases, MS&D assigned to Bliss & Wetherbee (B&W) (plaintiff) its rights against Western Oil. B&W sued Western Oil for breach of contract. B&W prevailed in the trial court and on appeal to the Court of Civil Appeals. Western Oil appealed.