Sentence:  Treatment of the conjugates with ethyl acetate , and the conjugates ( which had been passed through Dowex-2-chloride ) with mouse liver powder , sweet clover crown gall tissue powder , or healthy sweet clover proteins did not satisfactorily remove nonspecifically staining <WSD>substances</WSD> in the conjugates . 
Meaning of the word marked with <WSD> tags:  the real physical matter of which a person or thing consists