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336 



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the auditory nerve, is the soft 

 portion of the seventh pair of 

 cranial nerves, and forms the 

 special nerve of the organ of 

 hearing. 



Portulacacese, n. plu., port'-Hl-ok' 

 af-sb-e (L. porto, I carry ; lac, 

 milk), the Purslane family, an 

 Order of plants, so named from 

 their juicy nature : Portulaca, 

 n., port'ul-dk'd, (L. portiildca, 

 purslane), a genus of plants : 

 Portulaca oleracea, dl'-e'r-d'se-d 

 (L. olerd&us, herb - like from 

 olus, a kitchen herb), common 

 Purslane, used as a potherb 

 from its cooling and antiscor- 

 butic qualities. 



porus opticus, por'us tipt'ik-us 

 (Gr. poros, a pore ; optikos, 

 relating to the sight), the round 

 disc where the optic nerve 

 expands, and having in its 

 centre the point from which 

 the vessels of the retina branch. 



posology, n., poz-dl'd-ji (Gr. 

 posos, how much ; logos, dis- 

 course), the branch of medicine 

 which treats of quantity or doses: 

 posological, &.,pdz'dl'odj'ik'dl, of 

 or pert, to quantities or doses in 

 medicine. 



post-anal, a., post-dn'dl (L. post, 

 after or behind ; anus, the 

 fundament), situated behind the 

 anus : post-oesophageal, a., 

 eS'Oj'-adj-ef'dl (Gr. oisophagos, 

 the gullet), situated behind the 

 gullet : post-oral, or'-al (L. os, a 

 mouth, 6m, of a mouth), situated 

 behind the mouth : post-pharyn- 

 geal, a., situated behind the 

 pharynx. 



posterior, a., pdst-er'i'd'r (L. 

 posterior, hinder from posterns, 

 coming after), coming after ; 

 hinder ; in bot., applied to the 

 part of the flower next the axis 

 same as Superior : posteriors, 

 n. plu., the hinder parts of an 

 animal. 



posticse, n. plu., post'is-e (L. 

 posticus, behind), in bot., a name 



applied to anthers when they 

 open on the outer surface ; same 

 as ' extrorse, ' which see. 



PotamesB, n. plu., p^t-amf-e-e 

 (Gr. potdmos, a river), the Naias 

 or Pondweed family, an Order of 

 plants ; another name for ' Naiad- 

 acese,' which see : Potamogeton, 

 n., pb't'am'ddj'et'd'n (Gr. geiton, 

 bordering, contiguous), a genus of 

 plants whose species mostly grow 

 wholly in water : Potamogeton 

 natans, nat'-dnz (L. ndtans, 

 swimming), a species whose 

 roots are said to be eaten in 

 Siberia. 



potass, n., ptit-as' (potassa, a. 

 Latinised form of potash; F. 

 potasse, potashes), the hydrated. 

 oxide of the metal potassium, , 

 or kalium, much used in medic- 

 ine : liquor potassae, lik f >6r 

 pot-as'-se (L. liquor, a fluid ; 

 potassce, of potassa), a solution of 

 potass, a colourless and very 

 acrid fluid, prepared from car- 

 bonate of potass by adding 

 quicklime. 



Potentilleae, n. plu., pot'.ent-tt'-le-e 

 (L. potens, powerful, potentls, of 1 

 powerful), a Sub-order of plants, 

 Ord. Rosacese, so named from the 

 supposed medicinal qualities of 

 some of the species : Potentilla, 

 n., pot^nt'il'-ld, a genus of; 

 plants : Potentilla tormentilla, , 

 tor'-ment'iV-ld (L. tormentum, 

 pain or torment), a species whose 

 root was supposed to relieve pain 

 in the teeth, also tonic and 

 astringent. 



prsecipitate, n., pre-sip'it-dt (L. 

 prcecipito, I throw down head- 

 long), any substance thrown 

 down, from its state of solution 

 in a liquid, to the bottom of a 

 vessel, generally in a pulverised 

 form. 



prsefloration, n., pre'-flor-a'shun 

 (L. prcB, before ; flos, a flower, 

 fldris, of a flower), another term 

 for ' aestivation ' : praBfoliation, 

 n., pre f -f6l-i>a'.sliun (L. folium, 



