Sentence:  Two absorptions of * * f with ethyl acetate or two absorptions of * * f ( which had been passed through Dowex-2-chloride ) , NS and * * f with crown gall tissue powder , or <WSD>mouse</WSD> liver powder did not further improve the specificity of staining . 
Meaning of the word marked with <WSD> tags:  any of numerous small rodents typically resembling diminutive rats having pointed snouts and small ears on elongated bodies with slender usually hairless tails