Sentence:  More potent a charm to bring back that time of life than this record of a few pictures and a few remembered facts would be a catalogue of the minutiae which are of the very <WSD>stuff</WSD> of the mind , intrinsic , because they were known in the beginning not by the eye alone but by the hand that held them . 
Meaning of the word marked with <WSD> tags:  the tangible substance that goes into the makeup of a physical object