Sentence:  Even in the midst of the full swing of fancy, swayed to and fro by the many currants of thought that arise out of a single word, snatches of the verse from which the flight was taken will suddenly appear on the surface like a refrain or a keynote, showing that in reality there is a connexion, though hidden to the <WSD>uninitiated</WSD>. 
Meaning of the word marked with <WSD> tags:  Of a person, not having the special knowledge of a particular group.