SOURCE: A Grammar of the Latin Language, by D. Yenni (1845) at GoogleBooks. Although it is very much in the spirit of the classical Aesop, this exact cat-and-mouse fable is not one that is cataloged by Perry.
READ OUT LOUD. Choose which marked text you prefer to practice with - macrons or accent marks - and read the text out loud until you feel comfortable and confident. Then, try reading the unmarked text at the bottom. It should be easy for you after practicing with the marked texts. :-)
MACRONS. Here is the text with macrons:
Mūrēs, in pariete cavō commorantēs, diū contemplābantur fēlem, quae capite dēmissō et tristī vultū placidē recumbēbat. Tunc ūnus ex iīs: Hoc animal (inquit) admodum benignum et mīte vidētur esse. Quid sī alloquar et familiāritātem cum illō contraham? Quae cum dīxisset et propius accessisset, ā fēle captus et dīlacerātus est.
ACCENT MARKS. Here is the text with ecclesiastical accents, plus some color-coding for the words of three or more syllables (blue: penultimate stress; red: antepenultimate stress):
Mures, in paríete cavo commorántes, diu contemplabántur felem, quae cápite demísso et tristi vultu plácide recumbébat. Tunc unus ex iis: Hoc ánimal (inquit) ádmodum benígnum et mite vidétur esse. Quid si álloquar et familiaritátem cum illo cóntraham? Quae cum dixísset et própius accessísset, a fele captus et dilacerátus est.
UNMARKED TEXT. Here is the unmarked text - after practicing with the marked text that you prefer, you should not have any trouble with the unmarked text:
Mures,
in pariete cavo commorantes,
diu contemplabantur felem,
quae
capite demisso et tristi vultu
placide recumbebat.
Tunc unus ex iis:
Hoc animal (inquit)
admodum benignum et mite v
idetur esse.
Quid si alloquar
et familiaritatem cum illo contraham?
Quae cum dixisset
et propius accessisset,
a fele captus et dilaceratus est.
IMAGE. Here is an illustration for the story (image source) showing some mice in dangerous proximity to a cat!