 <unk> : During the early 1940s , quinine was the chief anti @-@ <unk> drug . Made from the bark of the South American <unk> tree , quinine was in short supply during the war , so scientists began searching for an alternative treatment . The test subjects allowed themselves to be bitten by <unk> mosquitoes and when the fever reached its peak in three to four days , were given experimental treatments . At the University of Minnesota , twelve CPS men underwent tests to determine the recovery period for those infected with malaria . This research documented the debilitating effects of the disease and the amount of time required for a complete recovery . 
