ARACHNITIS 



106 



ARCHEBIOSIS 



consisting of five kinds of glands, over one thousand 

 in all, producing a secretion insoluble in water and 

 with a nitrogenous basis, forming the fine, silky threads 

 of the web. 



Arachnitis (ar-ak-ni'-tis) [hpdx^l, a spider's web; /rig, 

 inflammation]. Inflammation of the arachnoid mem- 

 brane of the brain. 



Arachnoid tar - ah'- uoid) \_dpdxvt], a spider's web ; 

 eldoq, form]. Resembling a web. A. Cavity, the 

 space between the arachnoid membrane and the dura 

 mater. A. Membrane, the delicate serous membrane 

 of the brain and cord between the dura and pia mater. 

 Sub-arachnoid fluid. See Cerebrospinal Fluid. 



Arachnoidal (ar-ak-noid' '-al) \apdxvq, a spider's web; 

 eldog, form]. Pertaining to the arachnoid. 



Arachnoiditis (ar-ak-noid-i' -tis). Same as Arachnitis. 



Arachno-pia (ar - ak'- no -pi'- ah) [apdxvr/, a spider's 

 web; pia, fern, of pins']. The arachnoid and the pia 

 considered together. 



Arachnorrhinitis (ar-ak-nor-in-i' '-lis) [dpdjw?, spider; 

 p/f, nose ; ctlc, inflammation]. A disease of the nasal 

 passages supposed to be due to the presence of a spider. 



Arachnotitis (ar-ak-no-ti' '-lis) [ap&xi'V, spider ; ovg, 

 ear; trig, inflammation]. Inflammation said to be 

 caused by a spider in the auditory canal. 



Arack (ar'-ah) \_Ind.\ A spirituous liquor distilled 

 from rice, dates, palm-sap, or cocoanut juice, used in 

 Asia, etc. 



Araeometer (ar-e-om'-et-er). See Areometer. 



Araeotic (ar-e-of -ik). See Areotic. 



Aralia (ar-a f -le-ah) [L.]. A genus of plants, order 

 Araliaceae, embracing several species, having aromatic, 

 diaphoretic, and resolvent properties. Ginseng, wild 

 sarsaparilla, petty morrel, and other plants esteemed in 

 popular medicine belong here ; few have active quali- 

 ties of high value in any disease. Unof. 



Aran-Duchenne's Disease. See Diseases, Table of. 



Araneae Tela (ar-a'-ne-e te'-lah). See Cobweb. 



Araneous (ar-a f -ne-us) \aranea, a spider's web]. Full 

 of webs ; resembling a cobweb. A. Membrane, 

 the arachnoid. 



Arantius, Bodies of. See Corpora. A., Canal of. 

 See Canal. A., Duct of. See Duct. A., Nodules 

 of. See Arantius, Bodies of. A., Valves of. See 

 ValvulcB arantii. A., Ventricle of, a small cul-de-sac 

 in the medulla oblongata. 



Arar {a'-rar) [Barbary]. The tree Callitris quadri- 

 valvis of N. W. Africa. It produces sandarac. 



Araroba (ar-aro'-bah) [Brazil]. Goa Powder. An 

 oxidation product of resin found deposited in the wood 

 of the trunk of the Andira araroba of Brazil. Its 

 active principle is Chrysarobin or Chrysopliamc acid, 

 q. v. It is largely used in skin affections. 



Arasa (ar-a'-sah) [S. Am.]. The root of a plant 

 native to Brazil and Uruguay. The active principle of 

 the drug is found in the tuberosities of the root, espe- 

 cially in the bark, which is quite thick. In taste a 

 decoction of the drug resembles that of cascarilla. It 

 is an excellent remedy in metrorrhagia, acting where 

 hydrastis is ineffectual. No unpleasant secondary 

 effects have been noted. Unof. 



Arbor (ar'-bor) [L.1. A name for the arbor vita- of the 

 cerebellum. A. Vitae, a term applied to the arbores- 

 cent appearance of a section of the cerebellum, and 

 also to a similar appearance of the folds of the interior 

 of the cervix uteri. See Thuja. 



Arborization (ar-bor-iz-a' -shun) [arbor, a tree]. A 

 form of nerve termination in which the nerve fibers 

 are brought into contact with the muscle fiber by 

 means of an expansion. 



Arbuscula (ar bus' -ku-lah) [L.]. A small shrub hav- 

 ing the appearance of a diminutive tree. 



Arbutin (ar'-bu-tin) [arbutus, the wild strawberry tree], 

 C 12 Hj 6 O r A bitter glucosid obtained from Uva ursi, 

 orbearberry. It is neutral, crystalline, and resolvable 

 into glucose and hydroquinon. Arbutin is an efficient 

 diuretic. Dose gr. xv— xxx. See Uva ursi. 



Arbutus (ar-bu'-tus) [L.]. A genus of ericaceous 

 shrubs and trees. A. menziesii, the madrono of 

 California, has an astringent bark, useful in diarrheas. 

 Unof. A. unedo, the European arbute, is astringent 

 and narcotic. A., Trailing. See Epigaa. 



Arc [ark) \_arcus, a bow]. In craniometry, a measure- 

 ment taken on the outside of the skull, following its 

 curves. A., Binauricular, a measurement from the 

 center of one auditory meatus to the other, directly up- 

 ward across the top of the head. A., Bregmato- 

 lambdoid, a measurement along the sagittal suture. 

 A., Naso-bregmatic, from the root of the nose to the 

 bregma. A., Naso-occipital, measurement from the 

 root of the nose to the lowest occipital protuberance. 



Arcanum (ar-ka'-num) [arcanum, a secret]. A medi- 

 cine whose composition is kept secret. 



Arcate (ar'-kat) \arcatus, bow-shaped]. Bow-shaped; 

 curved ; arcuate. 



Arch (arch) \arcus, a bow]. A term applied to the 

 curved shape of several various parts of the body. A. 

 of Aorta. See Aorta. A., Branchial, the cartilagin- 

 ous arches that support the gills (branchiae) of fishes. 

 In the human fetus they are also present. See Cleft. 

 A. of Colon. See Colon. A. of Corti, the arch that 

 the pillars of the organ of Corti make over the basilar 

 membrane of the cochlea. A , Crural. See Pou- 

 parts Ligament. A. of Fallopius, a name for the 

 arch formed by Poupart's ligament. A. Femoral, 

 same as A. Crural. A., Palmar, the arch formed by the 

 radial artery in crossing the bones of the metacaipus. 

 A., Plantar, the arch made by the external plantar 

 artery. A., Post-oral, arches in the fetus, five in num- 

 ber, that develop into the lower jaw and throat. See 

 A., Branchial. A. of Pubes, that part of the pelvis 

 formed by the convergence of the rami of the ischia 

 and pubes on each side. A., Supra -orbital, the curved 

 and prominent margin of the frontal bone beneath the 

 superciliary ridge, that forms the upper boundary of 

 the orbit. A. of a Vertebra, the part of a vertebra 

 formed of two pedicles and two laminae and enclosing 

 the spinal foramen. A., Zygomatic, the arch formed 

 by the malar and temporal bones. 



Archaeocyte (ar'-ke-o-slt) [dpxalog, ancient ; nvrog, a 

 hollow (a cell)]. In biology, one of the irregular 

 ameboid cells — mesameboids — imbedded in a jelly-like 

 matrix and occurring between the two primitive epi- 

 thelia of the body, in the Porifera. 



Archaeostoma, Archaeostome (ar-ke-os'-to-mah, ar'- 

 ke-o-stom). See Archistome. 



Archaeus (ar-ke'-us) [apxaloq, ancient]. In spagiric 

 medicine, the invisible counterpart of the visible body ; 

 solar heat as a source of life. 



Archamceba (ark-am-e'-bah) [apxv, primitive; auoiffi, 

 change]. HaeckePs hypothetical progenitor of all 

 amebae and of all higher forms of life. 



Archamphiaster, or Archiamphiaster (ark-am-fe-as*' 

 ter, or ar-ke-am-fe-as' -ter) \jipxv, nrst > a ! l <Ph around ; 

 aari/p, star]. In biology, those amphiasters concerned 

 in the production of the polar globules. 



Archangelica (ark-an-jel' -ik-ah) [apxayy&Mdc, arch- 

 angel]. A genus of umbelliferous plants; A. abropur- 

 purea, officinalis, and sativa afford Angelica Root, ,/.:■. 



Archebiology (ar-ke-bi-ol'-o-je) [apxil, beginning ; 

 life ; 7.6yoq, discourse]. The study of the simplest or 

 most primitive forms or beginnings of life. 



Archebiosis (ar-ke-bi-o'-sis) [apxf)> the beginning ; 

 (Jiuoig, life]. The theoretical origin of living organ- 



