This little poem comes from Disticha de Educatione of Urbano Appendini, published in 1834; you can see the whole book at Google Books.
Carmen Non Longum
Altius in nostris defixum mentibus haeret
Quidquid non longo carmine praecipitur.
The vocabulary is keyed to the DCC Latin Vocabulary list. There are only two words in this poem not on the DCC list:
dēfixus, -a, -um: stuck, attached, fastened
haereō, haerēre: stick, cling to
altus -a -um: high, lofty; deep
carmen -inis n.: song
in: in, on (+ abl.); into, onto (+ acc)
longus -a -um: long, far; longē: far, far off
mēns mentis f.: mind
nōn: not
noster nostra nostrum: our
praecipiō -cipere -cēpī -ceptum: anticipate, advise, warn
quisquis quidquid: whoever, whichever