periosteal 
periosteal i per-i-os'ie-al ). ii. [(periosteum + 
-ill.] Investing or covering bone or a bone; 
of or pertaining to periosteum: as. /u-i-insti-nl 
tissue: /H-rinxtiiil vessels. 
periosteotome (pcr-i-os'tc-o-t6m>. . [< <;r. 
"-ipiuf-inr, periosteum. + -ro/".i;,< r/i/i'f/r, -niitir, 
cut.] A knife for dividing the periosteum. 
perioSteOUS (per-i-os'te-us), . [< />/r/>..^<Mi 
+ -mix. ] Same as jH-rinnli ill. 
periosteum (per-i-os'te-um), n. [= !'. /I/VI'/.A-// 
= Sp. It. l>l I'in.-itill = I'g- /X'l'I'lxll'O, < NL. pl'filtn- 
li inn, \Ai. /n'rioK/fini. < <ir. *m-pi&OTH\ I he mc'in- 
brane around the bones, neut. of xi/viin-un', 
around the bones (rftpioffreoc r/if/r, the mem- 
branearounil the bones), (iripi, around, + oariov, 
bone. | The envelojiing membrane of bones; 
n dense fibrous membrane firmly investing the 
surface of bones, except where they are cov- 
ered by cartilage. Its Innermost or osteogenlc layer 
produces bone-substance, and the whole membrane fur- 
ther serves in the attachment of softer parts and the sup- 
port of blood-vessels. Compare enditgteum. 
periostitic (per'i-os-tit'ik), a. [< perwsiitia + 
-ic.] Of or pertaining to periostitis; affected 
with periostitis. 
The association of the osteo-artliritic and periostitic le- 
sions suggested a similar origin for both. 
Lancet, No. 3409, p. 404. 
periostitis (per''i-os-ti'tis), . [NL., < p< //'.-- 
tfitm + -i'fjtf.] Inflammation of the periosteum, 
periostracal (per-i-os'tra-kal), a. ttperioftra- 
CIIHI + -ii/.] Investing the shell of a mollusk, 
ns an epidermis ; of or pertaining to periostra- 
cum. 
periostracum (per-i-os'tra-kum), . [NL., < 
Gr. at pi, around, + bcrrpaKov, shell.] The hornv 
epidermal investment of the shells of most mol- 
lusks. 
periotic (per-i-o'tik), . and n. [< Gr. mpi, 
around, + ovf (ur-), the ear: see otic.] I. a. 
Surrounding and 
containing the inner 
ear, or essential or- 
gan of hearing ; com- 
posing or entering 
into the formation 
of the otic capsule, 
or otocraue ; otocra- 
uial ; petromastoid ; 
petrosal or petrous. 
Several periotic bones 
are found in nearly all 
vertebrates. They may 
all remain distinct 
throughout life, but they 
are usually more or less 
confluent with one an 
other, and may be, as in 
man, completely fused ; 
furthermore, they may 
ankylose with other cra- 
nial bones, and thus give 
rise to certain parts of 
the compound temporal 
bone. Thepartsof askull 
called mastoid are com- 
monly outgrowths of per- 
iotic bones. The set of 
periotic bones composes 
a bony case for the inner 
ear, much as the case of 
a watch covers the works, 
and this Is termed the 
PrO 
4401 
rm; walk about (cf. -rpi-iiT:^, a walking about. 
a public walk, esp. a covered walk, hence dis- 
cussion, argument)/ -//', about. + -tin n; walk, 
< -<i-i. a path, walk: sec /.//Mi. The literal - 
is later in E.] I. a. 1. Walking about ; itine- 
rant. 
The plaintive cries of the chair-sealers, frog-venders, 
and certain other jx-rijiatetic merchant*, the meaning of 
whose vocal ailvi HIM mrntx I i-milil never penetrate. 
LmceU, Fireside Travels, p. -2-24. 
2. [cap.] Of or pertaining to Aristotle's system 
of ] ihilosophy, or the sect of his followers ; Aris- 
totelian: as, the I'tri jink-tic philosophers. 
And an hundred and slxtle yeares before Christ flour- 
ished Arlstoliulus, a lew, and PeripateMe Philosopher. 
Purchat, Pilgrimage, p. 174. 
II. . 1. One who walks about ; an itinerant ; 
a pedestrian. 
The horses and slaves of the rich take up the whole 
^trrrt ; while we peripatetics are very glad to watch an op- 
portunity to whisk across a passage. 
Steele, Taller, No. 144. 
2. [.cap.] A follower of Aristotle (384-322 B.C.), 
a great Greek philosopher. lu the middle ages 
the word was often used to signify a logician. 
See Arixtotelianism. 
The Platonists denied the great doctrine of the Peripa- 
tetics that all the objects of the human understanding en- 
ter at first by the senses. 
It. Stewart, Philos. of the Mind, L 1. 
3. pi. Instruction after the manner of Aristo- 
tle; instruction by lectures. 
The custom [of instructing by lectures] is old ; it is not 
merely a mediaeval one it belongs with hieroglyphics, 
cuneiform inscriptions, and peripatetic*. 
The Nation, XLVIII. 308. 
peripatetical (per*i-pa-tet'i-kal), a. [< peri- 
patetic + -al.] Same as peripatetic. 
The proud man Is known by his gait, which hperipateti- 
cat, strutting like some new church-warden. 
Rev. T. Adams, Works, I. 4S6. 
Peripateticism (per'i-pa-tet'i-sizm), n. [= Pg. 
lt.peripatetifismo(cf. Y.peripatetisme= Sp. Pg. 
It. peripatetismo) ; a.s Peripatetic + -wn/.] The 
philosophical doctrines of Aristotle and his fol- 
lowers ; the philosophy of the Peripatetics. See 
Aristotelianism. 
From first to last, Arabian philosophers made no claim 
to originality ; their aim was merely to propagate the truth 
of Peripateticimn, as It had been delivered to them. 
Encyc. Brit., II. 267. 
Peripatidae (per-i-pat'i-de), n.pl. [NL., < Peri- 
patus + -idte.] The only family of Peripatidea , 
containing the genus Peripatus. 
Peripatidea (per'-i-pa-tid'e-a), n. pi. [NL., < 
Peripatus + -idea.] An order of articulates 
periphrase 
periphacitis (pcr'i-fa-si'iiM. /-. [NL.. < *ir. 
TI/H, around, 4- OM;, lentil (taken 
' i-pa-tid 
a.] An 
the sii 
Periotic Capsule of Turtle 
inittas ). Upper figure Internal and 
lower figure external view of section 
united 
otocrane, otic capsule, or 
tkull of the ear. When 
opbthotic, with //<>, epiotic 
with SO, the supraoccipltal ; asc, esc, 
ftc, anterior, exterior, and posterior 
semicircular canals; /o,/r, fenestra 
ovalis. fcnestra rotunda; HO, exoc- 
cipital ; BO. basioccipital : B S, basi- 
sphenoid : / " and /'///. exits of trige- 
minus and auditory nerves ; P, pitui- 
tary space ; fa, parietal bone : Pi, 
pterygoUt. 
mastold parts are super- 
added, the resulting lM>ne is called pctromastoid. The hu- 
man periotic bones form what are called the petrous and 
KMUfoirf sections of the temporal bone. Periotic bones 
which have been distinguished and named in various ani- 
mals arc the epiotic, prodtic, opirthotic, and pterotic. Se 
these words, and cut under hyoid.- Periotic fenestra, 
a cavity or depression included by the conspicuous supe- 
rior semicircular canal, in the fetus or infant. 
II. ii. A periotic bone. 
peripapillary (per-i-pap'i-la-ri), a. [< Gr. irepi, 
around, + NL. papilla, papilla: see pajiillary.] 
Situated or occurriug around the circumference 
of the optic papilla. 
peripateciant (per -i-pa-te'shan), n. [For "peri- 
jinti Hi-inn (= F. iirr!jHiti : >ii-ii'n), (peripatetic + 
-a.] A peripatetic. Bp. Hull. 
I will watch and walk up and down, and be a peripate- 
i in n mill ii philosopher of Aristotle's stamp. 
'iiv, ,(c, Friar Bacon ana Friur Bungay. 
peripatetic (per'i-j4-tot'ik). //. and . [= F. 
l'< ri/i<iti : ti</iii' Sp. jH-ripati'tieo =r Pg. It. / i-/- 
/iii/rlicn. peripatetic. < L. /Y; - i//M/V/w, Peripa- 
tetic, of the Peripatetic school ; as a noun. /'/ n- 
pateticits, a disciple of this school (in ML. also 
simply a logician) ; < Gr. mparanpixif, given to 
walking about, esp. while teaching or disputing 
(said of Aristotle and his followers, 01 lli-pixttTrfn- 
KOI, the Peripatetics, because Aristotle taught 
in the walks of the Lyceum at Athens 1. < -rpixa- 
established upon the single genus Peripatus. 
It has been variously referred to the worms and the myria- 
pods, or elevated to the rank of a peculiar class. The 
same group, variously cited or considered In classification. 
is called Malacopoda, Onychophora, and f'rotracheata. Also 
Peripatetic, Penpati, Peripatoda. 
peripatidean (per'i-pa-tid'e-an), a. and . [< 
Peripatidea + -an.] I. a. Pertaining to the 
Pcrinatidea, or having their characters. 
II. . A member of the Peripatidea. 
Peripatus (pe-rip'a-tus), n. [NL., < Gr. mpi- 
mjrof , a walking about. KtpiKartiv, walk about : 
see peripatetic.] 1. A genus of myriapods, 
constituting the family Peripatidx. it is a syn- 
thetic or generalized type, supposed to be the living rep- 
resentative of an ancestral form like that from which all 
insects are descended. It has been at different times con- 
sidered a mollusk, a worm, and an insect ; it is now known 
to be a myriapod. It resembles a galley-worm or miUeped, 
having a long extensible cylindrical body capable of coiling 
up in a spiral like a thousand-legs, and has a gait like a 
caterpillar, the body being supported upon simple legs 
(17 to 33 pairs in the different species) ending In claws, 
placed along nearly the whole length of the body. At 
least 14 species are known. One was first described from 
the island of Saint Vincent in the West Indies, under the 
name P. iul\formi, from its resemblance to an lulus or 
milleped. P. capermt inhabits the Cape of Good Hope, 
and /'. ii<ir<i--''?"ii<ir;i is found in New Zealand : others 
occur in South America, Australia, etc. They are found 
nmong the decaying wood of damp and warm localities, 
and have the curious habit of throwing out a web of vis- 
cid tllaments when handled or otherwise irritated. 
2. [/. '.] A species of this genus. 
peripetalous (per-i-pet'a-lus), a. [< Gr. irrpi, 
around, 4- irtra)av, a leaf (petal) : see petal.] 
1. In rooV., situated around or about the peta- 
loid ambulacra of a sea-urchin. 2. In bot., 
situated around the petals. 
peripetia (per'i-pe-ti'a), n. [= F. peripetie = 
.Sp. Pg. peripetia = It. peripezia, < NL. peripe- 
ti>i, < Gr. irepnrtTeia, a turning right about, a sud- 
den change, < Trcpiircrfc, falling around, < n 
Tri-Ten', fall around, < vfpi, around, + K'I--UV, 
fall.] That part of a drama in which the plot 
is unraveled and the whole concludes: the 
denouement. 
as 
+ -itiii. Of. pliacitix.] In finllml., inflamma- 
tion of the capsule of the h-ns. 
peripharyngeal (per i-fa-rin'je-al). . [X Gr. 
->i>i, aronadj + ^ir;t (?>"/"';/-) the throat: see 
lilinryngeal.] Surrounding the pharynx: as, 
the jim/ilnni/ii'liul Imnd of cilia of some itsci- 
dians. peripharyngeal band, In ascMlnns, a tract 
of large cilia which Hum>tinds tin- oral :ip'-i1m of tbr 
pharynx, and niny IM- continuous with a similar hypo- 
pharyngeal band, as It Is In Appendicularia. Huxley, 
Anat. Invert, p. 612. 
peripherad (pe-rif'c-ra<l). mlr. [< j:mjilifr-i/ 
+ -HtP.] Toward the periphery; away from 
the center: the opposite of cintnnl. liurl.\ 
1 In iHiiioiii; <if .Ml. Sfii-ni-fs. VIII. ."1:1:;. 
peripheral (pc-rif'e-ral), a. [< peri/ilii-i--;/ + 
-til.] Of, belonging to, or situated on the pe- 
ri|ihery, circiiinference, or surface generally; 
characteristic of or constituting the periphery : 
as, fii -i -i/i/iii -ill parts: iii-riiilifrnl expansion. 
Acute peripheral encephalitis. Same as perieneepha- 
lit!*. Peripheral akinesla, akfnesla due to lesion of the 
anterior coniua of the spinal gray matter, or of the motor 
nrrvrs or of the muscles, or. In a more restricted sense, of 
tlie nerves or muscle* alone. Peripheral anaesthesia, 
anaesthesia due to lesion of the sensory nerves, or end- 
organs. Peripheral epilepsy. s- ev ne v t v . Periph- 
eral organs, in zool., organs distinctly separated from the 
main part of the body, as the feet and feathers of a bird, 
the wings of an insect, etc. 
peripherally (pe-rif'e-ral-i). adc. On or from 
the periphery or exterior surface; as regards 
the periphery: as, peripherally acting inhibi- 
tory nerves. 
peripheric (per-i-fer'ik), a. [= F. ptriplierique 
= Pg. periplicrico = It. periferico ; as periflier-y 
+ -ic.] 1. Pertaining to or constituting a 
periphery. 2. Situated around the outside of 
an organ ; external : in botany, noting an em- 
bryo curved so as to surround the albumen, fol- 
lowing the inner part of the seed-covering. 3. 
In zool., radiate : noting the type of structure of 
the Cuvierian radiates. See tuassiee, 6. Tow 
Baer. 
peripherical (per-i-fer'i-kal), n. [< periplifrii- 
+ -al.] Same as periphenc. 
peripherically (per-i-fer'i-kal-i ), rfr. Periph- 
erally. [Kare.] 
periphery (pe-rif 'e-ri), . ; pl.Mmpfteries (-riz). 
[Early mod. E. periferic ; < ME. periferie, < OF. 
peripheric , F. periplterie = Kp. perifeiia = Pg. 
periplieria = It. periferia, < LL. peripheria, 
ML. also periferia, <' Gr. irtptfyipeia, the Hue 
around a circle, circumference, part of a circle. 
an arc, the outer surface, < mpityepiif, moving 
around, round, circular, < Ktpityepeiv, carry 
around, move around, < ffp', around, + ifiipeiv 
= E. bear 1 .'] 1. In geom., the circumference 
of a circle ; by extension, the boundary-line of 
any closed figure ; the perimeter. 
I An] imperfect run nde declining toward a longitude, ami 
yet keeping within one line for his periferie or compasse 
as the rounde. Puttenham, Arte of Eng. Poesle, p. 84. 
2. The outside or superficial parts of a body; 
the surface generally. 
There are two distinct questions involved in this un- 
solved problem. The first relates to the transmission of 
a nervous Impulse from the periphery to the sentient cen- 
tres. .'. Stdly, Sensation and Intuition, p. 39. 
Fire of the periphery. See fire. 
periphlebitic (per*i-fle-bit'ik), . [< periphle- 
bitis + -ic.] Of or pertaining to peripnlebitis. 
periphlebitis (per"i-fle-b!'tis), . [NL., < Gr. 
mot, around, + ^1/1 (V/t/3-), vein, + -itis. Cf. 
phlebitis.] Inflammation of the outermost coat 
of a vein. 
periphoranthium (per'i-fo-ran'thi-um), n. 
[NL., < Gr. irept<tx>/>A, a circuit (< nepi&fpeii', move 
around : see periphery), + oi^or, a flower.] In 
bot., same aspericlinitini. 
periphractic (per-i-frak'tik), a. [< Gr. irtpi- 
QpaKTof, fenced around, inclosed, < mpuppaaativ, 
fence around, < irepi, around, + ifipaaaetv, fence : 
see phragma.] Having, as a surface, such a 
form that not every closed line within it can 
shrink to a point without breaking. Thus, ai - 
anchor-ring is a iieriphractic surface. 
periphrase (per'i-fraz), w. [< F. periphrase = 
Sp. perifraxis, perifrast = Pg. periphrase = It. 
perifrasi, < L. jieripJtrasiit, circumlocution: see 
periphrasis.] Same SLS periphrasis. Imp. Diet. 
periphrase (per'i-fraz), . ; pret. and pp. peri- 
phrased, ppr. periphrasing. [= F. perinhraser 
= Sp. perifrasear = Pg. periphrasear = It. peri- 
frasare; from the noun.] I. trans. To express 
by periphrasis or cireunilocution. 
II. hitnnin. To use circumlocution, fmp. 
Diet. 
