As such, {TAIL ~ the main body} 12, by itself, is essentially a conduit through which {HEAD ~ material} may pass 
As such , { TAIL ~ the main body } 12 , by itself , is essentially a conduit through which { HEAD ~ material } may pass
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH