isthmus (or th silent), istmus, isthim

[Lat. isthmus, from Gr. isthmos.] 1. Ord . Lang . & Geog .: A narrow slip or neck of land connecting two continents together, or unit ing a peninsula to a continent. 2. Anat .: The name given to various parts which more or le closely resemble an isthmus. There is an isthmus of the thyroid body, an isthmus uteri, . Isthmus of the fauces : Anatomy.: The constricted pa age between the anterior pillars leading from the mouth to the pharynx. Isthmus of the thyroid body or gland: Anat .: A transverse portion of the gland uniting the two lateral lobes. Is-ti-õph-or-a, s . pl . [Gr. istion =a web, cloth, or sheet, and phoros =bearing, carrying.] Zool .: A group or division of Insectivorous Bats having a nose-leaf; but Mr. Dobson, who has deeply studied the subject, considers the arrangement unnatural, Is-u-rět, s . [Eng. is(omeric), and -uret (q. v.).] Chem.: Hydroxyl-methenyl-diamine. This base, which is isomeric with carbamide, is formed by the direct union of hydrocyanic acid with an alcoholic solution of hydroxylamine. It crystallizes in rhombic prisms, which are soluble in water, insoluble in alcohol, and melt at 104°-105°. It has an alkaline re-action, and unites with one equivalent of acid, forming crystalline salts. On boiling the aqueous solution, it decomposes in a very complicated manner, yielding nitrogen, carbon dioxide, ammonia, guanidine, biuret, and urea. It, *hit, *hyt, pron . [A. S. hit , neut. of he (q. v.); Icel. hit , neut. of hinn ; Dut, het , neut. of hij . The genitive case its is comparatively modern. It does not occur once in the Authorized Version of 1611, and is found but three times in all Shakespeare, and not once in Milton, although other writers had already begun to introduce it. In some parts of the country the rustics still employ his where educated men would use its . In Levit. xxv. 5, where the modern editions read " of its own accord," the edition of 1611 has " of it own accord." The A. S. gen it. his was regularly used as the gen it. of it up to the time of Shakespeare.] 1. A pronoun of the neuter gender corresponding with the masculine he and feminine she , the plural of all three being they . It is frequently cla ed as a demonstrative. "Keep thy heart with all diligence, for out of it are the i ues of life." -Proverbs iv. 23. 2. It is used as the nominative to impersonal verbs; as, It rains, it snows. 3. It is commonly used to introduce a sentence, preceding a verb as a nominative, but referring to a clause or distinct member of the sentence following; as, It is well known that he is dead. 4. It is frequently used to begin a sentence when a personal noun, or the name of a person, or a masculine or feminine noun follows, and it may represent any one of the three genders, or either the sing ular or the plural number; as, " It is I, be not afraid," " It is these," . When a question is asked, it follows the verb; as, Who was it that betrayed Christ? 5. It is used absolutely for the state of a person or thing; as, "How is it with the general?" ( Shakesp .: Coriolanus , v. 5.) 6. It is used indefinitely after intransitive verbs, frequently imparting a ludicrous meaning. "If Abraham brought all with him, it is not probable that he meant to walk it back again for his pleasure." Raleigh. It-a-bal-11, s. [The Guiana name.] Bot.: (See etym. and compound.) it a ball i-wood, s. Bot.: The wood of Vochya guianensis . It is hard but not very durable. I-tab-ir-yte, I-tab-Ir-ite, s. [From Itabira , a mountain in Brazil.] Min . & Petrol .: A micaceous variety of hematite, found in micaceous schist in North and South Carolina, . Called also specular schist (q. v.). ( Dana .) 1-ta-col-u-mite, I-ta-col-u-myte, s. [From Itacolumi =the Giant, the name of several Brazilian mountains.] Petrol.: A laminated granular flexible quartz rock, with a little talc, found in Brazil, Georgia, North Carolina, the Ural Mountains, . It sometimes contains diamonds and gold. Rutley spells the word Itacolumite and Dana Itacolumyte. 1-ta-con-Ic, a . [Formed by transposition from aconitic (?).] (See the compound.) itaconic-acid, s . Chem.: C3H4(COOH)2. A bibasic acid, isomeric with citraconic and mesa conic acids, obtained by the dry distillation of citric acid, whereby its water is first driven off and then aconic acid is formed. 2388 C3H4(OH) (COOH)3=OH2+C3H3(COOH)3, the latter further decomposing into CO2 and itaconic acid. C3H3(COOH)3=CO2+C3H4(COOH)2. It may also be prepared by heating to 160° a mixture of citric acid and water in a sealed tube. Itaconic acid is inodorous, but has a strong acid taste. It crystal lizes in rhombic prisms, soluble in 17 parts of water at 10° and melting at 161°. It bears a close resemblance to citraconic acid, but differs from it in not yielding mesa conic acid when treated with nitric acid. It-a-ka, s. (The Guiana name of the tree.] Bot.: (See etym. and compound.) itaka-wood, s. Bot. & Comm.: A kind of wood with black and brown streaks, much used in cabinet work. It comes from Machærium schomburgkii , a papilionaceous tree, tribe Dalbergieæ, growing in Guiana. I-tal-iạn (1 as y), a. & s. [Ital. Italiano ; Lat. Italic us , from Italia =Italy; Sp. Italiano .] A. As adj .: Of or pertaining to Italy. B. As substantive: 1. A native or inhabitant of Italy. 2. The language spoken by the Italians. Italian-beech, s. Bot. The same as ITALIAN-OAK (q. v.). Really an oak, and in no respect a beech. Italian-iron, s . A laundre ' smoothing-iron for fluting and smoothing frills; a gauffering-iron. IMG:content-0080.png:[blocks in formation] Italian-marble, s . [MARBLE.1 Italian-may, s . Bot.: Spirœa filipendula . Italian-oak, s . -ite