INTERSTITIA: The intervals supposed to elapse, according to Roman Catholic canon law, between the times of a man's receiving the different orders. The principle that there should be such intervals is expressly laid down in the thirteenth canon of

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the Council of Sardica (343). It was observed in regard to the minor orders as long as they had distinct functions, but this ceased when they became mere formal steps to the higher. The Council of Trent endeavored to restore their former actual significance, and prescribed the observance of the interstitia for them, unless the bishop should judge it better to proceed otherwise. At the present day it is customary in many places to confer the tonsure and all the minor orders on the same day. It was also decreed at Trent that a year should elapse between the minor and major orders, and between each of the latter, unless necessity or the general good required the time to be shortened, and that two major orders should never be conferred on the same day. In reference to the bishop's dispensing power, moreover, the Congregation of the Council has positively forbidden the conferring of the minor orders and the subdiaconate at the same time.

(F. W. H. WASSERSCHLEBEN†.)

BIBLIOGRAPHY: L. Thomassin, Vetus et nova ecclesiæ disciplina, I., ii. 35-36; P. Hinschius, Das Kirchenrecht . . . in Deutschland, i. 112-113, Berlin, 1869; G. Philips, Kirchenrecht, i. 648 sqq., Regensburg, 1881; A. L. Richter, ed. W. Kahl, Lehrbuch des . . . Kirchenrechts, p. 364, Leipsic, 1886; E. Friedberg, Lehrbuch des Kirchenrechts, p. 139, ib. 1895.

INTINCTION. See EASTERN CHURCH, III., § 5.

INTRODUCTION TO THE BIBLE. See BIBLICAL INTRODUCTION.

INTROIT: The name given in the Latin Church to the anthem at the beginning of the communion service. It usually consists of an antiphon, a verse (or more) from a psalm or other portion of Scripture, and the Gloria Patri (see LITURGICS, III., § 2). It differs considerably in the different rites in name, contents, and the time of its performance. Numerous forms exist, the Pian Missal alone containing 159. The origin is debated, some ascribing it to Pope Celestine (423 A.D.; cf. Liber pontificalis, ed. Mommsen in MGH, Gest. pont. Rom., i. 94, 1898), and others to Gregory the Great.

BIBLIOGRAPHY: L. Duchesne, Christian Worship, pp. 116-117, 163, 190, 439, London, 1904; DCA, i. 865--867.