In 1961, Monsanto filed a new application claiming another large class of compounds, again including 3,4-DCPA and 3,4-DCAA and again asserting that the class possessed "unusual and valuable herbicidal activity." Again, the Patent Office rejected the application as unpatentable over the prior art. In 1967, Monsanto applied again, this time claiming only 3,4-DCPA and representing only that 3,4-DCPA had "unusual and valuable herbicidal activity" and that its activity was "surprising" because "related compounds possess little or no herbicidal efficiency."