Page:Cyclopaedia, Chambers - Volume 2.djvu/868

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THUS. See Frankincense.

THUMMIM, in the Scripture Learning. See Urim and Thummim.

THURSDAY. See Week.

Maunday Thursday. See Maunday Thurfday.

THYMUS, in Anatomy, a conglobate Gland, fituated in the upper Part of the Thorax, under the Clavicuhe, where the Cava and Aorta divide into the Subclavian Branches. See Gland.

This Gland is big in Infants, but as they grow in Age, it grows lefs ; its Arteries and Veins are Branches of the Carotides and Jugulars. It has Nerves from the Par Vagum, and its Lyuiphatick Veffels dilcharge them/elves into the Ducfus Thoracicus.

The learned Dr. Tyfon fuppofes the Uie of this Gland to be for a Diverticulum to the Chyle in the Thoracick Ducf of a Fcetus, whofe Stomach being always full of the Liquor in which it fwims, muft keep the Thoracick Duel diitended with Chyle ; becauie the Blood which the Fcetus receives from the Mother, fills the Veins, and hinders the free Entrance of the Chyle into the Subclavian Veins. See Foetv.

M. Chefelden obferves, that where the 'thymus in Men is very fmall, the Thyroid Glands encreafe proportionably ; but in fuch Brutes as have fallen under his Obfervation, it is iulf. the contrary ; from which he is inclined to believe that they belong to the lame Lymphatics, and that either of them encreafing as much as both ought to do, if both encreafed, anfwers the fame End as both did ; and that the Reafon why the Thymus encreafes rather than the Thyroid Glands in Brutes, is, becaufe the Shape of their Thorax affords con- venient Room for it to lodge in ; and that in Men, the Realbn why the Thyroid Glands encreafe lb much, is, be- caufe there is no Room in that part of the Thorax where the Thymus is feated, for a large Gland to be lodg' d.

The Thymus is that, which in a Breaft of Veal we call the Sweat-Bread.

Thymus, in Medicine, is ufed fof a kind of Wen, grow- ing on the natural Parts, the Fundament, and feveral other Places of the Body, with cloven Afperities like thole of the Herb Thyme, whence its Name. See Wen.

The ordinary Method of curing a Thymus, is by Ligature and deficcative Lotions, or by Cauftic's ; and if large, by Incifion ; taking Care firfl to fecure the greater Veffels by tying them.

THYREOARYTjENOIDEUS, in Anatomy, a Pair of Mufcles, fituate under the Cartilago Thyreoides ; from the fore and back Patt of which, it arifes with a very broad Head, and terminates in the Arytainoides, which it con- ftringes, and fhuts the Larynx. See Arytjenoides.

THYROIDE.E Glandule, Thyroid Glands, are two Glands of the Larynx. See Larynx.

There are Four pretty large Glands, which ferve to moiflen the Larynx; two above and two below.

The two latter are call'd Thyroidal ; fituate at the bottom of the Larynx, afide of the Annular Cartilage, and of the firft Ring of the Trachea ; one on each Side.

They ate in form of little Pears; their Colour a little more reddifh, their Subfiance more folid, more vifcous, and refembling more rhe Flefh of the Mufcles, than the other Glands. .

They receive Nerves from the Recurrents, Arteries from the Carotides ; Veins which pafs to the Jugulars, and Lym- phaticks, which difcharge themfelves into the Thoracic Duff. ,.

Their Ufe is to feparate a vifcid Moifture, fetving to line, and lubricate the Larynx, to facilitate the Motion of its Cartilages, to foften the Acrimony of the Saliva, and to fweeten the Voice.

THYROIDES, in Anatomy, one of the five Cartilages of the Layrinx. See Larynx.

The firft, and biggeft of the Cartilages of the Larynx is call'd Thyroides or Scutiformis, by reafon of its Figute, which fome fancy to referable a Shield. It ishollow within, and gib- bous without fide ; but more lb in Men than in Women. In the middle is a Prominence, call'd Pomum Adami. 'Tis ufu- ally parted by a Line running along the middle ; whence fome make two of it ; tho' in teality 'tis very rare 'tis found double.

It is near a Square ; and at each Angle is a Procefs : The two uppermoft are the longeft, and tie it by means of a ner- vous Lioament to the Os Hyoides : The two lower, and .fliorter °conne£f it to the fecond Cartilage, call'd Crkoides. TheWord is form'd from the Greek, ^ypsof, Buckler, and

£/©-, Form. . - ',

THYRSUS, in Antiquity, the Scepter which the ancient Poets put in the Hand of 'Bacchus, and wherewith they furnilli the Menades in their ■Bacchanalia. See Baccha-

" TheV^T/KS was originally a Lance, or Spear, wrapt up in Vine-Leaves; wherewith Bacchus is faid to have arm d himfelf and his Soldiers in his Indian mm, t" amufe and deceive the unpraftifed Indians, and make them fufpect no Hoffilities.

Hence it was afterwards bore in the Feafts and Sacrifices of that God ; and as the Satyrs, who were Bacchus's Soldiers, were fuppofed to have fought with it, it became a Cuttom to reprefent them therewith. See Satyr Sic.

The Wotd is form'd from the Greek, »u f n&, Haftula fron- dibus vejiiti, figniiying the fame thing.

TIARA or Thiara, an Ornament or Habit, wherewith the ancient 'Perfians cover'd their Head ; and which the Armenians, and Kings of Pontus flill wear on Medals ; thefe laft, becaufe defended from the Perfians^ The Latin Authors call it indifferently, Tiara or Cidarii. Strata fays, the Tiara was in form of a- Tower: The Scholiaft on ^7n/2i#>,fez«es's Comedy, 'Aowpw, A3 j. Scene 2. affirms, that it was adorn 'd with Peacock's Feathers. Some Mo- derns, however, take it, the Scholiaft is here fpeakinp of the Cask which the ancient Perfians wore in War ; rather°than the Habit which they wore on the Head in the Cities : But they don't feem to have confider'd the Paffage in the Poet, to which the Scholiaft refers: The Matter thereTpoke of is Peace, and EmbafTadors fent to treat of Peace, with Habits of Pomp and Ceremony, "Aj^^a; yi, s^ c . Thefe Ambajfadors, thefe 'Peacocks, all theje Things of Pomp and Ofientation difpleafe me. By thefe 'Peacocks, fays the Scholiaft, he means the Tiar<e, which among the 'Perfians are Ornaments of the Head, wherein are Peacock's Featheis, i§c.

St. Jerom on Tlan. cap. iv. defines the Tiara a kind of Cap, genus Pilleoli, wote by the Perfians and Chaldeans. In another Place, he adds, 'tis like Ulyffes's Cap.

The ancient Scholiaft, on Juvenal, defcribes the Tiara as a Prieft's Cap, which defending over the Cheeks, was tied under the Chin ; which agrees very well with the Form of that which we fee Mithridates wear, on Medals. Senilis on Virgil, lib. viii. JEneid. calls the Tiara, a Phrygian Cap ; and Statins, Thebaid, lib. viii. gives it the Kings of Parthia, who, doubtlefs, borrowed it from the Perfians.

Juftin attributes the long Garment and Tiara of the Perfi- ans, to Semiramis's Difguife ; whereby fhe pafs'd for Nynus. The Kings of Perjia alone, had the Right of wearing the Tiara ftraight and upright : The Priefts, and great Lords wore it deprefs'd, or turn'd down on the Fore-fide. Xenophon in his Cyropad. fays, that the Tiara was fometimes encompafs'd with the Diadem, at leaft in Ceremonies ; and had frequently the Figure of a Half Moon embroider'd on it ; Others are of Opinion, that 'twas the Diadem had the Fioure of a Moon, and that it was hence the Tiara was call'd Lll'iiata ; and, laftly, others think that the Tiara itfelf was fometimes in form of a Half Moon. From whatwe have faid it appears, that there were different Forms of Tiara's ; and| in effecf, Pafchalius, de Cormis, fhews there were Five different Kinds. See Diadem.

Tiara is alfo the Name of the Pope's Triple Crown 1 anciently call'd ReBtUni. See Crown.

The Tiara, and Keys are the Badges of the Papal Dignity"; the Tiara of his Civil Rank, and the Keys of his Jurifclicfi- on : For, affoon as the Pope is dead, his Arms are reprefented with the Tiara alone, without the Keys.

The ancient Tiara was around high Cap, JohnXXlll. firft encompafs'd it with a Crown. Boniface VIII, added a fecond Crown; and BeKe.?5S the Xllth, a Third.

TIBIA, in Anatomy, the bony Part of the Leg, between the Knee and the Ankle. See Leg.

The Tibia confifts of two Bones, call'd Fociles, the one on the Infide the Leg, call'd the Fibula, or little Focil. See Fibula.

The other on the Out-fide, call'd by the common Name Tibia, or the great Focil. See the following Article.

Tibia, is, properly, rhe inner and bigger Bone of the Leg, call'd alio Foctle Majlis. See Bone.

The Tibia is hard and firm, having a pretty large Cavity in its Middle, to contain the Medulla. See Medulla.

Ir is almoft Triangular ; its fore, and fharp Edge being call'd the Shin : in its upper Extremity, it has two large Sinus's, tipt with a foft and fine Cartilage, from its Figure, call'd Cartilago Lunata ; which runs in between the Extre- mities of the two Bones, and grows very thin at its Edge; ferving to facilitate a fmall Side-motion in the Knee, like thofe in the Articulation of the lower Jaw.

The Sinus's receive the two Protuberances of the Femur, or Thigh-bone ; and the Production which is between the Sinus's of the Tibia, is received into the Sinus, which divides thefe two Protuberances of the Femur. See Femur.

By bending the Knee, we bring the Leg, in walking, in a flrait Line forwards ; which we could not have done without this Articulation ; but like thofe who have the Misfortune to have a wooden Leg, we muft have brought our Foot about in a Semi-circle, in going even upon a Plain, but more evidently upon an Afcenr.

On the Side of this upper End, it has a fmall Knob, which is received into a fmall Sinus of the Fibula, and on its Fore- part, a little below the Patella, it has another into which the Tendons of the Extenfors of the Leg, are inferted. See Fibula.

Its