Sentence:  Specific staining by DEAE-cellulose treated * * f and * * f , although clearly distinguishable under the microscope from either <WSD>nonspecific</WSD> staining or autofluorescence of cells , was not satisfactorily photographed to show such differences in spite of many attempts with black and white and color photography . 
Meaning of the word marked with <WSD> tags:  not caused by a specific agent; used also of staining in making microscope slides