854. There are two kinds of perfect stems: (A.) Some verbs have as
perfect stem a root, generally with some modification, but without a
suffix (858-866). (B.) Some perfects are formed with a suffix, #-s-#, or
#-v-# or #-u-# (867-875).
855. Some perfects of primitives are formed not from a root, but from
the present stem without the formative vowel, treated as a root: as,
#prehendī#, _seized_, from #prehend-# (866); #poposcī#, _asked_,
#fefellī#, _deceived_ (858); #iūnxī#, _joined_ (867).
856. The first person of the perfect ends in #-ī#, sometimes written
#ei# (29, 2). #-t#, #-stī#, sometimes written #-stei# (29, 2), #-stis#,
and #-mus# are preceded by short #i#; #-re# is always, and #-runt# is
usually, preceded by long #ē#: as,
#rēxī#, #rēxi-stī#, #rēxi-t#, #rēxi-mus#, #rēxi-stis#, #rēxē-runt#
(#rēxe-runt#), or #rēxē-re#.
857. Sometimes #-t# is preceded by long #ī#: as, #iīt#, #petiīt#,
REDIEIT (29, 2). #-runt# is sometimes preceded by short #e# (Plaut.,
Ter., Lucr., Hor., Ov., Verg., Phaedr.). This is the original form;
#-ē-# is by analogy to #-ēre#.
(A.) PERFECT STEM WITHOUT A SUFFIX.
858. (1.) Some verbs in #-ere# form their perfect stem by prefixing to
the root its initial consonant with the following vowel, which, if #a#,
is usually represented by #e#; this is called the _Reduplicated
Perfect_, and the first syllable is called the _Reduplication_: as,
PERFECT STEM. VERB. FROM THEME.
pu-pug- pungō, _punch_ +pug-+
pe-pig- pangō, _fix_ +pag-+
Other examples are: #cadō#, _fall_, #cecidī# (#cad-#, 104, _c_);
#pariō#, _bring forth_, #peperī# (#par-#, 104, _c_); #pellō#, _push_,
#pepulī# (#pol-#, 105, _h_); #poscō#, _demand_, #poposcī# (855);
#fallō#, _deceive_, #fefellī# (855, 104, _c_); see also 923-932.
#caedō#, _cut_, has #cecīdī# (108, _a_); and a few old forms are quoted
from verbs having an #o# or an #u# in the root with #e# in the
reduplication: as, #memordī#, #pepugī#.
859. Four verbs with vowel roots also have a reduplicated perfect stem:
#dō#, _give_, _put_, #dare#, #dedī#; #bibō#, _drink_, #bibere#, #bibī#;
#stō#, _stand_, #stāre#, #stetī#, and #sistō#, _set_, #sistere#,
#-stitī#, rarely #stitī#. Also four verbs in #-ēre#: #mordeō#, _bite_,
#momordī#, #pendeō#, _hang_, #pependī#, #spondeō#, _promise_,
#spopondī#, #tondeō#, _clip_, #-totondī#. In the root syllable of
#spopondī#, _promised_, #stetī#, _stood_, #stitī#, _set_, and the old
#scicidī#, _clove_, an #s# is dropped (173, 2).