Scanning is measuring a verse as you are measured by your tailor—by the foot, according to rule. To scanning there belong the figures called Synalœpha, Ecthlipsis, Synæresis, Diæresis, and Cæsura.
Synalœpha is the cutting off a vowel at the end of a word, before another at the beginning of the next; as
Ōcclūsīs ēvāsi ŏcŭlīs nāsōquĕ cruēntō:
I came off with my eyes bunged up and a bloody nose.
We have here knocked out an i in evasi, on the strength of a synalœpha.
But heu and o are never cut off—at least there are no cases on record in which this operation has been performed.
Ecthlipsis is as often as the letter m is cut off with its vowel; the next word beginning with a vowel, as
Mōnstrum hōrrēndum īnfōrme īngēns—spectāvĭmŭs hōrtīs:
We saw a horrible, ugly, great monster in the gardens.
If every bear and boar were kept in a den—what a fine world this would be.