allowing the second reagent to be absorbed through {HEAD ~ the top layer} of the pad to activate the first reagent by flowing through {TAIL ~ the rupturable seal} after breaking to form an activated chemical test pad in the sealed package 
by flowing through
allowing the second reagent to be absorbed through { HEAD ~ the top layer } of the pad to activate the first reagent by flowing through { TAIL ~ the rupturable seal } after breaking to form an activated chemical test pad in the sealed package
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH