The substantially non dissolvable region remains substantially intact as the dissolving region is progressively dissolved, introducing the functional agent into {HEAD ~ a flowing stream} of {TAIL ~ water} 
of
The substantially non dissolvable region remains substantially intact as the dissolving region is progressively dissolved , introducing the functional agent into { HEAD ~ a flowing stream } of { TAIL ~ water }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL