act 
a medicine acts, uvrkx, or operates ; a plan wwfat or op- 
rrair*. Where they differ, act may mine often refer to a 
single action or to the simpler forms of action : as, a ma- 
chine mirk-x well when all its parts act. Act may also he 
the most general, applying to pel-sons or thing*, the oth- 
ers applying generally to things. Operate may express 
the more elaborate forms of action. Work may express 
the more powerful kinds of action : jus, it worked upon his 
minil. 
acta (ak'ta), n. ]>l. [L., pi. of aetum: see act, 
.] 1. Acts. Specifically 2. Proceedings in 
a legal or an ecclesiastical court, or minutes 
of such proceedings Acta (or Actus) Apostolo- 
rum (Acts of the Apostles), the title in the Vulgate of 
the fifth hook of the New Testament. Acta Martyrum 
(Acts of the Martyrs), contemporary accountsof the early 
Christian martyrdoms, from judicial registers or reports 
of eye-witnesses, or as drawn up by the ecclesiastical 
notaries; specifically, the critical edition of such acts by 
the Benedictine Hninart, first published in 1689, and the 
additional collections by the Orientalist Stephen Assemani, 
in 1748. -Acta Sanctorum (Acts of the Saints), a name 
applied generally to all collections of accounts of saints 
and martyrs, both of the Roman and Greek churches ; 
specifically, the name of a work begun by the Bollandists, 
a society of Jesuits, in 1G43, and not completed until 1870. 
It now consists of sixty -one folio volumes, including an in- 
dex published in 1875. 
actable (ak'ta-bl), a. [< act + -able. ,] Practically 
possible; performable; capable of being acted. 
Is naked truth actable in true life ? 
Tennyson, Harold, iii. 1. 
Mr. Browning set himself to the composition of another 
aftiihle play. The Century, XXIII. 199. 
Actaea (ak-te'a), n. [L., herb-christopher, from 
the resemblance of the leaves to those of the 
elder, < Gr. auraia, 
erroneous form 
of atiria, contr. 
d/cn/, the elder- 
tree.] A genus of 
herbs, natural or- 
' der Ranuncula- 
cew, with some- 
what deleterious 
properties. The 
old-world species, A. 
nuicata, the bane- 
berry or herb-chris- 
topher, has black 
berries. The com- 
mon forms of North 
America with red 
berries are now con- 
Red Uaneberry (Acttra riibra), showing sidered Varieties of 
flowering plant and fruiting raceme. the same Species, but 
the white-berried A. 
alba is kept distinct. In the Atlantic States these are 
known as red and white cohoslt or baneberry. 
Actaeon (ak-te'on), n. [L., < Gr. 'AKraiuv, in 
myth. , a grandson of Cadmus, who, having come 
accidentally upon Diana bathing, was changed 
by her into a stag, and then torn to pieces by 
his own dogs. Cf . dwaZof, on the coast, < O.KTII, 
a coast, headland, edge.] 1. The representa- 
tive genus of the molluscan family ActteonicUv. 
Originally written Acteon. Montfort,18W. Also 
Tornatella. 2. A genus of abranchiate gastrop- 
ddous mollusks, of the family Elysiidte (which 
see): a synonym of Elysia. Oken, 1815. 
Actaeonella (ak-te-p-nel'a), n. [NL., < Act&on 
+ -eHo.] The typical genus of Actteonellidte, 
containing numerous species with thick conoid 
or convoluted shell, short or concealed spire, 
long narrow aperture, and the columella with 
three regular spiral plaits in front. Originally 
written Acteonella. D'Orbigny, 1842. 
actaeonellid (ak-te-6-nel'id), n. A gastropod 
of the family ActceonelKdce. 
Aetseonellidae (ak-te-6-nel'i-de), . pi. [NL., 
< Actueonella + -idee.] A family of gastropods, 
taking name from the genus Actceonella (which 
see). 
actaeonid (ak-te'on-id), n. A gastropod of the 
family Actaionidee. 
Actaeonidas (ak-te-on'i-de), n. pi. [NL.,< Aeta- 
<m + -(>/;.] A family of tectibranchiate gas- 
tropods, variously limited, but typified by the 
genus Actwon. It is now chiefly restricted to animals 
retractile in their shells and having a wide frontal lobe ter- 
minating behind in broad triangular tentacles ; uncinatc 
lingual teeth, which are numerous, nearly uniform, and 
arranged in series diverging from the middle ; and a sub- 
cylindrical spiral shell having a colnmellar fold. The liv- 
ing species are of small size, marine, and chiefly tropical 
see). 
act-drop (akt'drop), . In a theater, a curtain 
which is lowered between acts. 
Actenobranchii (ak-ten-6-braug'ki-i), n. pi. 
[NL., < Gr. d- priv. + Kreif (KTCV-), a comb, + 
jifidyxia, gills.] In Macleay's ichthyological 
system, one of five primary groups of fishes, 
characterized solely by the branchise not being 
pectinated like those of most fishes. It is a very 
59 
artificial group, composed of the Lophubranchii and Cy- 
'tuttn/ui HI M'ir*<i">lir<ni<iui. 
Actian (ak'shi-iin), a. [<L. Actius (poet.), also 
Actittciiit, a., < .Ictiiini, Gr. "Axrtov, lit. a head- 
land, < d/ir/), a headland. Cf. Actteon.] Relating 
to Actium, a town and promontory of Acarnania 
in Greece Actian games, games held from remote 
antiquity at Actium in lionor of Apollo, and reorganized 
and developed by Augustus to celebrate his naval victory 
over Antony near that town, Sept. 2, 31 B. c. As remod- 
eled by the Romans they were celebrated every four years, 
and became the fifth in importance of the great Greek fes- 
tivals. Hence, Actian years, years reckoned from the 
era of the new Actian games. Games also called Actian 
were celebrated, by senatorial decree, every four years at 
Rome. 
actinal (ak'ti-nal), a. [< Gr. auric (atnv-), a ray, 
+ -al. ] In zoo'i. : (a) Pertaining to the side of 
a radiate animal which contains the mouth: 
equivalent to oral, since the pole, surface, or 
aspect of the body whence parts radiate is also 
that in which the mouth is situated : the oppo- 
site of abactinal or aboral. The actinal side orsur- 
face may be the upper one, in the usual attitude of the ani- 
mal, as in the case of a sea-anemone, which is fixed by its 
abactinal or aboral pole, and grows upward ; or it may be 
the lower one, as in the case of a starfish, which creeps upon 
its actinal or oral surface. In a sea-urchin of more or less 
globular shape nearly the whole superficies is actinal. 
The so-called mouth is always placed at one end of these 
poles, and from it radiate the most prominent organs, in 
consequence of which I have called this side of the body 
the oral or actinal area, and the opposite side the aboral 
or abactinal area. 
L. Agassi!, t'ontrib. Nat. Hist. N. A., IV. 876. 
The mouth [of sea-urchins] is always situated upon the 
lower or actinal aspect, which is applied in progression 
to the surface upon which the animal moves. 
Stand. Nat. Hint., I. 161. 
(b) In general, having tentacles or rays. 
The upper extremity [of members of the genus Actinia] 
is called the actinal end, since it bears the tentacles or 
rays. Dana, Corals, p. 22. 
Actinellida (ak-ti-nel'i-da), n. pi. [NL., < Gr. 
auric, (UKTIV-), ray, + dim. -ell-us + -tcfar.] A fam- 
ily name of radiolarians : synonymous with As- 
trolophididai (which see). 
ActinellidSB (ak-ti-nel'i-de), n. pi. [NL.,< Acti- 
nella (not used) + -idee.] A family of acantho- 
metrous acantharians with the skeleton com- 
posed of a varying number of spicules, which 
are not distributed according to J. Miiller's law. 
actinenchyma (ak-ti-neng'ki-ma), n. [< Gr. 
auric, (auriv-), ray, + eyxvpa, infusion, < iyxiuv, 
pour in.] In bot., a name that has been given 
to a system or tissue of stellate cells. 
acting (ak'ting), p. a. Performing duty, ser- 
vice, or functions ; specifically, performing the 
functions of an office or employment tempo- 
rarily: as, an acting governor or mayor; an 
acting colonel or superintendent. In the United 
States there is generally some officer of lower grade legal- 
ly entitled to become the acting incumbent of an impor- 
tant executive office during a temporary vacancy from 
absence or disability of the elected incumbent. Tempo- 
rary vacancies in military, judicial, and minor executive 
offices are usually filled by assignment or appointment. 
Actinia (ak-tin'i-a), . [NL., < Gr. dxr/f (O.KTIV-), 
ray.] 1. Agenus of zoophytes, belonging to the 
Kadiata of Cuvier, regarded as the type of the 
order Malacodermata, subclass Zoantharia, class 
Aetinozoa, subkingdom Ccelenterata, in modern 
classification. The body is cylindrical, and is attached 
by one extremity, the mouth occupying the middle of the 
upper or free extremity. The mouth is surrounded by 
concentric circles of tentacles, which when spread re- 
semble the petals of a flower, whence the popular names 
animal-flowers and sea-anemones (which see). They are 
not perfectly radial in symmetry, the common polyp of 
the sea-shore, A. meftembryanthemum, having the oral 
aperture slightly elliptical, the long axis being marked by 
a tubercle at either end ; the animal thus presents a faint 
but well-marked indication of bilateral symmetry. They 
move by alternately contracting and expanding their bases, 
and by their tentacles. The species are often of brilliant 
colors ; many of them are used as food. See Aetinozoa. 
2. [/. c.] An animal of the genus Actinia or 
family Actiniidce. 
Actiniadae, n. pi. See Actiniidce. 
Actiniaria (ak-tin-i-a'ri-a), n. pi. [NL., < Ac- 
tinia + -aria.] One of the divisions of the class 
Aetinozoa, containing the sea-anemones, and 
nearly equivalent to the order Malacodermata. 
actinic (ak-tin'ik), a. [< Gr. auric, (O.KTIV-), a ray, 
+ -.] Pertaining to actinism; having the 
property of actinism. 
The so-called actinia rays, which were discovered by 
their special activity in connection with the earlier pho- 
tographic processes, but which can now be changed into 
visible rays, are merely vibrations too rapid to affect the 
eyes. Tail, Light, 3. 
Actinic process, a generic name for any photographic 
process ; specifically, any photo-engraving process. 
actinically (ak-tin'i-kal-i), adv. As regards the 
chemical action of the sun's rays. 
The light which finally emerges, however much cor- 
rected, becomes more and more actinically weak. 
Silver Sunbeam, p. 35. 
actinoid 
Actinidse (ak-tin'i-de), n.pl. Same as 
iiln: ./. l>. Jtni/ii, 1846. 
actiniforin(ak-tin'i-f 01111 or ak'tin-i-form), a. [< 
<>r. i/AT/'f (auriv-), ray, + L. -/ormfe.</l>ma,form,] 
Haying a radiated form ; resembling an actinia. 
Actiniidae, Actiniadae (ak-ti-ni'i-de, -a-de), . 
pi. [NL., <. Actinia + -i<ln; -ada'.] The sea- 
anemones or animal-flowers proper, regarded 
as a family, having as type the genus Actinia, 
and belonging to the order Helianthoida or 
MalttciidrriHiitit, of the class Aetinozoa. It con- 
tains numerous genera and species. See Acti- 
nii.:ini. Also written Actinit/n . 
actiniochrome (ak-tin'i-o-krom), n. [< Gr. OK- 
r/f (UKTW-), ray (see actinium), + xP"/^ a i color.] 
A red pigment obtained by Moseley from some 
specimens of Runod.es craxsus, one of the Ac- 
tinogoa. 
actinism (ak'ti-nizm), . [< Gr. <kn'f (CIKTIV-), 
ray, + -wm.] If. The radiation of heat or light, 
or that branch of natural philosophy which 
treats of the radiation of heat and light. 
2. That property of the sun's rays which, as 
seen in photography, produces chemical com- 
binations and decompositions. A pencil of rays, 
when decomposed by refraction through a prism, is found 
to possess three properties, viz., the heating, the lumi- 
nous, and the chemical or actinic. It was formerly sup- 
posed that the actinic property belonged peculiarly to 
the more refrangible part of the spectrum, beginning with 
the violet and extending far beyond the visible spectrum ; 
it is now known, however, that the different rays differ 
essentially only in their wave-lengths, and that the phe- 
nomena of heat, light, or chemical action observed depend 
upon the surface on which the rays respectively fall. The 
violet end of the spectrum acts especially on the sensitive 
silver salts, but the chemical decomposition of the carbon 
dioxid (COo) in the atmosphere involved in the growth 
of vegetation takes place most actively under the action 
of the yellow rays ; and under proper conditions a pho- 
tograph of even the ultra-red rays at the opposite end of 
the spectrum may be obtained on a gelatin plate sensitized 
with silver bromid. 
actinium (ak-tin'i-um), n. [NL., < Gr. dx-rif (d/c- 
riv-), ray.] A supposed chemical element found 
associated with zinc. Its chemical and physi- 
cal properties have not been fully investigated. 
actino-. [NL.,etc., <Gr. d/crif (CMTLV-), ray: see 
actinic."] An element in scientific compounds 
of Greek origin, meaning ray. In chemical com- 
pounds it represents specifically actinism. 
Actinocheiri, . See Actinochiri. 
actino - chemistry (ak"ti-no-kem'is-tri), n. 
[< aclin-ism + chemistry. ~\ Chemistry in its re- 
lation to actinism. See actinism.' 
Actinochiri (ak'ti-no-kl'i-I), . [NL., < Gr. 
aKTtf (ciKTtv-), ray, + xeip, hand.] An order of 
fishes having six unpaired and one pair of basilar 
bones supporting the pectoral fin, and all ar- 
ticulating with the scapula. Its only known repre- 
sentatives form the extinct family Pelecoptei-idce, of the 
Upper Cretaceous formation. Cape, 1875. Also spelled 
Actinocheiri. 
Actinocrinidae (ak"ti-no-krin'i-de), n.pl. [NL., 
< Actinocrinm + -ida:~\ A family of encrinites, 
or fossil crinoids, exemplified by the genus Ae- 
tinocrinus. 
actinocrinite (ak"ti-no-kri'nlt), 11. [< Actino- 
crinus + -ite 2 ."] An encrinite, or fossil erinoid, 
of the genus Actinocrinim. [By error some- 
times spelled actinocritt.~\ 
Actinocrinus (ak"ti-u6-kii'nus), n. [NL., < Gr. 
auric, (auriv-), ray, + Kpivov, lily: see crinoid.\ 
A genus of encrinites, or fossil crinoids, re- 
ferred to the family Encrinidce, or made type 
of the family Actinocrinidce. L. Agassiz, 1834. 
actino-electricity (ak^ti-nd-e-lek-tris'i-ti), n. 
[< actin-ism + electricity.'] Electricity produced 
in a body (e. g., rock-crystal) by direct heat- 
radiation. Hankel. 
Actinogastra (ak"ti-n6-gas'tra), n. pi. [NL., < 
Gr. N d/cr/f (CIKTIV-), ray, + yaar!if>, belly.] In 
Haeekel's classification, a subclass of Asterida, 
containing those starfishes or sea-stars which 
have the gastric cavity radiated, whence the 
name. 
actinograph (ak-tin'o-graf), 11. [< Gr. d/cr/f 
(attriv-), ray, + -y/ja<j>eiv, write. Cf. Gr. aKnvo- 
ypa(f>ia, a treatise on radiation, of same forma- 
tion.] An instrument for measuring and re- 
gistering the variations of actinic or chemical 
influence in the solar rays. The intensity of this 
influence bears no direct relation to the quantity of light, 
but varies at different periods of the day and of the year. 
There are sevei'al forms of actinograph, all of them using 
the same test, namely, the depth of the blackening effect 
of chemical rays allowed to fall on a sensitive piece of 
paper for a given time. 
actinoid (ak'ti-noid), a. [< Gr. aKTtvoeidt/s, < axrif 
(anTtv-), ray, + eWof , form: see -oid.] Having 
the form of rays ; resembling a starfish ; con- 
spicuously radiate : as, the actinoid type of 
echinoderms. 
