THINOCORO& 



TIIUOMBOLITR. 



UNO 



TH I NO'COHUS (EsohsoholU). a genui of Birds placed by Mr. O. R. 

 Qny in his sub-family rAinocoriiMe. 



THIRO'PTERA. [CHWBOITXBI.] 



THIRST U the peculiar sensation wbicb excites the desire to drink. 

 Water U the proper object of this desire. [FOOD.] 



THISTLE, the common name of Canluiu, a genus of Plant* belong- 

 ing to the Urge natural order Composite. From the time of Tbeo- 

 phnutua down to that of Caspar Bauliin, all planU that possessed a 

 spiny involucre were comprehended in the geuui C'arduiu. The 

 Artichoke (Cynara) and the Teasel (Diptacut) were included in it by 

 Tragus and Lobelia*. Moruon confined the genus to those plants that 

 had spiny scales of the involucre and a crown of feathery down 

 (pappus) surmounting the seed. PlanU resembling them, but with- 

 out a spiny involucre, he called CVr/ixm, and thoee without the feathery 

 pappus Carduui improprii diclui. Tournefort adopted these distinc- 

 tions. Vaillant defined Canlutu more accurately, giving it to plants 

 with a globular involucre composed of spiny scales, with compound 

 flowers, tubular florets, stamens united by the anthers, a hairy recep- 

 tacle, and a hairy pappus on the seeds. If the pappus was feathery, 

 he called the genus Acama ; and when the receptacle was not hairy, 

 but honeycombed, he used the term Onopordon, a name previously 

 applied to Thistles by Pliny. When the scales and receptacles were 

 fleshy, he named the genus Cynai-a. Linnrcus adopted these genera, 

 but changed Vaillant's Acama into Cnicta, a name which had been 

 previously employed by Tournefort for another genus. 



The genus Carduut consists of upwards of 30 species, moat of 

 which are inhabitants of Europe. None of them are found in the 

 New World. 



C. nutatu, Mink-Thistle, has decurreut spiny leaves, with handsome 

 drooping flowers ; the scales of the involucre cottony, the outer ones 

 spreading. It is a common plant on waste ground, in dry, stony, or 

 chalky soils, in Great Britain. It gives out, especially in the evening 

 in warm weather, a strong smell of musk. 



C. man'aniu, Milk-Thistle, has spinous leaves embracing the stem ; 

 the scales of the involucre leaf-like, recurved and spinous at the 

 margin. It is a native of England ; scarce in Scotland. The leaves 

 are distinguished by the milky-whiteness of their veins. This milki- 

 neas U said, according to an absurd story, to have been produced by 

 a drop of the Virgin Mary's milk, just as the Milky-Way was sup- 

 posed to arise from that of Juno. This plant is an esculent, and may 

 be eaten young as a salad, or boiled and eaten a* greens. The young 

 stalks, when peeled and soaked in water, are also excellent. 



The root may be prepared like saliify and skirret, and the receptacle 

 may be cooked and eaten as the artichoke. When cultivated, the 

 seeds should be sown in spring, and the plants kept at a foot and a 

 half distance from each other, and the earth thrown up round them 

 till they are etiolated. 



The genus Cnicut, Plume-Thistle, is known by the feathered down 

 that crowns the seeds. It is a large genus ; nine of the species are 

 inhabitant* of Great Britain. 



The Cotton-Thistle is the Onopordon, which is known by its honey- 

 combed receptacle. The 0. Acanthium is a British species. The 

 leaves are ovate-oblong, sinuated, spinous, Recurrent, and woolly on 

 both sides. It attains a height of from four to six feet. It is culti- 

 vated in Scotland as the Scotch Thistle; but it is doubtful whether this 

 national badge has any existing type, as the representations of the 

 Scotch Thistle on ancient wood-carvings, coins, and armorial bearings, 

 differ more from each other than any known species of thistles. The 

 raeepUele and stalk* of the Cotton-Thistle are sometimes eaten in the 

 same manner a* the Artichoke and Cordoon. [Cvx.vii.v.] 



The Carline Thistle forms the genus Cortina, which obtained that 

 name from a tradition that the root of the Common Carlino (C. nil- 

 yari$) was shown by an angel to Charlemagne as a remedy for the 

 plague which prevailed in hi* army. The genus is known from the 

 others by the inner scales of the involucre being spreading and mem- 

 branous, and of a yellow colour. The Common Carline is a frequent 

 plant in Great Britain on dry hilly pasture and in fields. It is about 

 one foot high. 



The Blessed Thistle is the Centaurta benedicta, the CardHtu bene- 

 ilirttu of old writers. The involucre of the genus L'entaurea if not spiny, 

 nntl the seeds have a very simple pappur, or none. The Blessed 

 TbUtle U a native of the Levant, and in the middle ages was held in 

 extravagant estimation on account of its supposed virtues. It is still 

 cultivated in some places on account of it* medicinal properties. 



Sow-Thi't !. is the name given to the species of .SoncAiu. [Soifcnus,] 



THLASPI (from tfAov, to comprers; seeds compressed), a genus of 

 PlanU belonging to the natural order C'rucifenr, and the sub-order 

 Anytulitrptir. It has a roundish notched pouch, boat-shaped valves 

 winged at the back ; the seeds are numerous the petals e^ual, the 

 flowers white. 



T. armtt, Penny-Crew, has oblong-toothed leaves and erect stems, 

 an elongated fruit-bearing raceme, orbicular pouches with a longitu- 

 dinal wing. It is a native throughout Europe and in England. The 

 flowers are small and white, and the whole plant when bruised has a 

 somewhat alliaceous odour. 



T. j*rfuliatum ha* obcordate pouches, the stem-leaves cordate- 

 oblong, the petals equal in length to the calyx. It is a native of 

 Europe and U found in England on a chalky soil 



T. alptttre is found on limestone mountain pastures throughout 

 Europe and England ; the leaves are entire, the radical ones ovate, 

 (talked, the cauline ones sagiUate and stem-clasping ; the petal* nearly 

 as long as the calyx, the pods obcurdate, 8-12-seeded. 



THOA (Liniucus), a genus of Polypiaria. 



THOMSONITE. [COMITOKITB.] 



THORA'CIC DUCT is the principal trunk of the lymphatic or 

 absorbent system, and the canal through which the greater part of the 

 chyle and lymph is conveyed into the blood. It commences, below, 

 at what is called the receptaculum chyli, which receives all the prin- 

 cipal absorbent vessels from the intestines and from the lower extre- 

 mities, and lies at the posterior and middle part of the abdomen, on 

 the upper lumbar vertebra and on the right Hide of the aorta. In 

 man the diameter of the receptaculum is but little greater than that 

 of the thoracic duct, which is continued from it ; in most other 

 animals it is considerably greater, and the duct seems in them to com- 

 mence in a large pouch. From the receptaculum chyli the thoracic 

 duct passes upwards, on the right side of the aorta, and behind it, 

 from the abdomen into the chest, being joined in its course by the 

 lymphatic vessels of the adjacent organs. Opposite the sixth dorsal 

 vertebra it begins to bend to the left, and, after passing behind the 

 arch of the aorta, it ascends to the level of the seventh cervical 

 vertebra, curves forwards and downwards, and open* into the left sub- 

 clavian vein, usually near its junction with the left jugular vein. At 

 this orifice of the thoracic duct there are two valves, like those of 

 the veins, which open to permit fluid to pass from the duct, but close 

 when any is forced against them from the vein. Other valves in un- 

 certain number are found in different parts of the duct, and have 

 all the same direction as those of veins. [ABSORBENTS; CHYLE; 



DIGESTION.] 



THORAX. [LuKos.1 



THORITE, a Mineral in which thoriua was discovered to exist by 

 Berzelius. It occurs massive and compact. Fracture uneven, very 

 brittle, and full of cracks. Hardness about 5-0. Lustre resinous ; 

 vitreous; opaque. Colour black. Specific gravity 4-63 to 4-80. Before 

 the blow-pipe, gives off water, and becomes yellow, but does not fuse. 

 It ia found in Sienite, in Norway. It contains nearly 58 per cent, of 

 thoriua, mixed with 13 metallic and other bodies. 



THO'RIUM, or THORI'NUM, a metallic body discovered by 

 Berzelius in an earth to which he had given the name of Thoriua. 

 [TnoiUTE.1 



THORN. [CRATJSUCS.] 



THORN-APPLE. [DATURA.] 



THOROUGHWORT. [EUPATOBIUM.] 



THOROW-WAX. [Bui'i-EUiiL-M.] 



THRA'CIA (Leach), a genus of Mollutca. 



TUItASA'ETOS. [FALCONIDJL] 



THRAULITE, J/inngcritc, llydrated Silicate of Iron, a Mineral 

 occurring in roundish nodules. Fracture uneven or imperfect, con- 

 choidaL Structure curved, foliated. Brittle. Splendent. Nearly 

 opaque. Lustre vitreo-resinoua. Colour brownish-black. Gives out 

 water when heated in a glass tube; imperfectly fused by the blow- 

 pipe, and is, after heating attracted by the magnet. It occurs at 

 Itiddarbyttan in Westinauland (1), and at Bodenmais in Bavaria (2), 

 accompanying iron pyrites. Its analyses by Hisinger and Kobell are 

 as follows: 



(I) Hiilnger. (2) Kobell. 



Silica 30-30 31-28 



Peroxide of Iron 44 '39 60'86 



Water 2070 19-12 



101-39 101.26 



THRIFT, the common name of the Notice Armeria, Smith, now 

 Armeria maritima. Armtria belongs to the natural order 1'lumbayi* 

 linear. It is distinguished by the flowers being iu a head contained 

 in an inverted cylindrical sheath, and the capsular fruit not bursting. 



A. maritima, Thrift, is a commou British plant, growing on muddy 

 and rocky sea-shores and on the bauks of salt-water actuaries. It 

 bears transportation to gardens, where it is a favourite in forming the 

 borders of flower-bed*. It may be easily distinguished from other 

 species by iU linear 1-uerved leaves. It has rose-coloured Cowers. 

 Several varieties are described. 



(Babington, Manual of Brititk Botany.) 



THRINCIA, a genus of Plant* belonging to the natural order 

 Compotitee and the sub-order Cichoractcc. It has an oblong involucre 

 in one row, with a few additional scales at the base ; the receptacle is 

 punctured; the fruit beaked; the pappus in two rows, the outer row 

 setaceous, deciduous, the inner one longer, feathery, and dilated at the 

 base ; the marginal row of fruiU enveloped in the scales of the 

 involucre. 



T. liirta, the only British specie.*, has lanceolate leaves, sinuate, 

 dentate, hispid or hairy; the leaves are all radical, sometimes nearly 

 or quite entire, occasionally runciuate. It is found chiefly in 

 gravelly soil. 



(Babington, Manual of Brilith Botany.) 



THIU'OTHORUS. [TROGLODYTE*.] 



THRIOTHU'RUa [TROOLODTTIHJS.] 



THROMBOL1TE. [COITER.] 



