The tool is thus lowered against the gel or membrane and pressed with sufficient force to penetrate the gel or membrane without penetrating the intermediate layer, thereby fully excising {HEAD ~ the spot} in the form of a disk from the gel or membrane without also excising {TAIL ~ any} of the intermediate layer 
The tool is thus lowered against the gel or membrane and pressed with sufficient force to penetrate the gel or membrane without penetrating the intermediate layer , thereby fully excising { HEAD ~ the spot } in the form of a disk from the gel or membrane without also excising { TAIL ~ any } of the intermediate layer
OTH OTH OTH OTH OTH OTH OTH OTH OTH 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 OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH