ATA 



39 



ATR 



during one generation, succeeded 

 by its reappearance in another ; 

 in zool,, the tendency of species 

 or varieties to revert to an original 

 type. 



ataxia, n., a- tabs' i> a (Gr. a, not, 

 without; taxis, order from tasso, 

 I put in order), want of co- 

 ordination in the movements of a 

 limb or organ, as * locomotor 

 ataxia ; ' want of co-ordination in 

 the movements of the arms or 

 legs, or both, depending upon 

 fascicular echrosis of the posterior 

 column of the spinal cord : ataxic, 

 a. , inco-ordinate : ataxic aphasia, 

 loss of speech, from want of co-or- 

 dination of the muscles employed 

 in articulate speech. 



atheroma, n., dth'-$r-6m'd (Gr. or 

 L. atheroma, a tumour filled 

 with matter ; Gr. athdra, a pap 

 made of meal), fatty calcareous de- 

 generations in the body ; a curdy 

 tumour: atheromatous, a., aih'- 

 er'dmf'dt'US, containing matter 

 of the nature of atheroma. 



atherosis, n., ath'-Zr-dz'-is (a word 

 formed from Gr. atherdma, a 

 tumour), chronic inflammation of 

 the internal coat of the arteries. 



AtherospermaceaB, n. plu., ath'Zr- 

 o- sperm- of- sZ-e (Gr. ather, the 

 awn or beard of an ear of corn ; 

 sperma, seed the seeds being 

 furnished with awns), the plume 

 nutmeg family, an Order of 

 plants: Atherospenna, n., ath'er- 

 6'Sperm'a, a genus of plants of 

 preceding Order : Atherosperma 

 moschatum, rnds-Tcdt'-um (mid. L. 

 moschdtus, having a smell like 

 musk from moschus, musk ; Gr. 

 moschos, a sprout, a shoot), a 

 native of Australia, the bark of 

 which resembles sassafras in 

 flavour, 



atlas, n., at'-lds (Gr. Atlas from 

 a, intensive ; tlao, I bear, I sus- 

 tain in the Greek mythology, 

 a giant who bore up the earth 

 upon his shoulders), the top joint 

 of the neck bones which support 



the globe of the head ; the first 

 vertebra of the neck. 



atlo-axoid, a., atf-lo-aks'-oyd (Eng. 

 atlas, the first vertebra of the 

 neck; Eng. axis, the second 

 vertebra of the neck; Gr. eidos, 

 resemblance), applied to the two 

 pairs of ligaments which connect 

 the atlas with the axis of the 

 vertebrae. 



atonic, a., a>t$n f -ik (Gr. a, with- 

 out; tonos, a tone), debilitated: 

 atony, n., at'-8n4 t debility; 

 muscular weakness. 



atrabiliary, a., dt'-rd-biM-dr-i (L. 

 ater, black ; bills, bile), melan- 

 cholic; hypochondriac. 



atractenchyma, n., at'-rak-ten'- 

 kim-a (Gr. atraktos, a spindle, a 

 distaff; chumos, juice, sap), in 

 bot., tissue composed of spindle- 

 shaped cells. 



Atriplex, n., dM-pttks (L. ater, 

 black ; plexus, plaited, twisted), 

 a genus of plants, Ord. Chenopod- 

 iacese: Atriplex hortensis, h$r- 

 tens'-is, garden Orach or wild 

 Spinach. 



atrium, n., dt'rt-um (L. atrium, 

 a front hall), the great chamber 

 or cloaca into which the intestine 

 opens in the Tunicata. 



atropal, n., dt f -rop-dl (Gr. a, with- 

 out; tropos, a turning), in bot., 

 an ovule in its erect position. 



Atropese, n. plu., at-rdp'8-e (Gr. 

 Atropos, in anc. mythology, one 

 of the Fates, whose duty it was 

 to cut short the thread of life), a 

 Sub-ord. of the Ord. Solonacese : 

 Atropa, n., dt r -rop-d, a genus of 

 plants : Atropa belladonna, b^l'* 

 Id-dMnd (see * belladonna '), 

 deadly nightshade, a highly 

 poisonous plant : atropia, n., 

 dt-rop'-i-a, and atropin, n., 

 dt'-rdp-m, a highly poisonous 

 alkaloid extracted from the root 

 of the 'Atropa belladonna,' form- 

 ing its active principle : atropism, 

 n., at'rop-izm, the symptoms pro- 

 duced by the frequent medicinal 

 use of belladonna. 



