Sentence:  After <WSD>titration</WSD> of the liberated * * f with * * f , aliquots of the aqueous and of the organic phase were counted in a solution type Geiger tube . 
Meaning of the word marked with <WSD> tags:  a measured amount of a solution of unknown concentration is added to a known volume of a second solution until the reaction between them is just complete; the concentration of the unknown solution (the titer) can then be calculated