Sentence:  When 1 ml of conjugate was passed through a <WSD>column</WSD> ( * * f ) , the first and second milliliter fractions collected were the most specific and gave no nonspecific staining in some experiments , and very little in others . 
Meaning of the word marked with <WSD> tags:  a vertical glass tube used in column chromatography; a mixture is poured in the top and washed through a stationary substance where components of the mixture are adsorbed selectively to form colored bands