The excision of sample spots from a gel or membrane by pressing a cutting tool terminating in a hollow cylinder against the gel or membrane supported on a rigid surface is made more reliable by interposing {HEAD ~ a relatively pliable, intermediate layer} on {TAIL ~ the side} of the surface facing the gel or membrane 
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The excision of sample spots from a gel or membrane by pressing a cutting tool terminating in a hollow cylinder against the gel or membrane supported on a rigid surface is made more reliable by interposing { HEAD ~ a relatively pliable , intermediate layer } on { TAIL ~ the side } of the surface facing the gel or membrane
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 OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH