Geraldine Coster, Psycho-analysis for normal people, Oxford University Press, 1928, p.96.

He generally does this by picking up little bits of ready-made philosophy here and there as he goes along, and sticking them on to his mind to protect it from harsh contacts, just as a caddis-worm sticks irrelevant fragments of rubbish on to his body as armour against his foes. We tend more especially to stick such pieces of philosophy over spots that life has made tender or susceptible.