The following is taken from :
http://www.newadvent.org/cathen/05709a.htm (catholic online encyclopedia)
ExorcismExorcism is (1) the act of driving out, or warding off, demons, or evil spirits, from persons, places, or things, which are believed to be possessed or infested by them, or are liable to become victims or instruments of their malice; (2) the means employed for this purpose, especially the solemn and authoritative adjuration of the demon, in the name of God, or any of the higher power in which he is subject.
The word, which is not itself biblical, is derived from exorkizo, which is used in the Septuagint (Genesis 24:3 = cause to swear; III(I) Kings 22:16 = adjure), and in Matthew 26:63, by the high priest to Christ, "I adjure thee by the living God. . ." The non-intensive horkizo and the noun exorkistes (exorcist) occur in Acts 19:13, where the latter (in the plural) is applied to certain strolling Jews who professed to be able to cast out demons. Expulsion by adjuration is, therefore, the primary meaning of exorcism, and when, as in Christian usage, this adjuration is in the name of God or of Christ, exorcism is a strictly religious act or rite. But in ethnic religions, and even among the Jews from the time when there is evidence of its being vogue, exorcism as an act of religion is largely replaced by the use of mere magical and superstitious means, to which non-Catholic writers at the present day sometimes quite unfairly assimilate Christian exorcism. Superstition ought not to be confounded with religion, however much their history may be interwoven, nor magic, however white it may be, with a legitimate religious rite.
Ecclesiastical Exorcisms:(1) Exorcism of the possessedWe have it on the authority of all early writers who refer to the subject at all that in the first centuries not only the clergy, but lay Christians also were able by the power of Christ to deliver demoniacs or energumens, and their success was appealed to by the early Apologists as a strong argument for the Divinity of the Christian religion (Justin Martyr, Apol., 6; P.G., VI, 453; Dial., 30, 85; ibid., 537, 676 sq; Minutius Felix, Octav., 27, P.L., III; Origen, Contra Celsum., I, 25; VII, 4, 67; P.G., XI, 705, 1425, 1516; Tertullian, Apol., 22, 23; P.L., I, 404 sq; etc). As is clear from testimonies referred to, no magical or superstitious means were employed, but in those early centuries, as in later times, a simple and authoritative adjuration addressed to the demon in the name of God, and more especially in the name of Christ crucified, was the usual form of exorcism.
But sometimes in addition to words some symbolic action was employed, such as breathing (insufflatio), or laying of hands on the subject, or making the sign of cross. St. Justin speaks of demons flying from "the touch and breathing of Christians" (II Apol., 6) as from a flame that burns them, adds St. Cyril of Jerusalem (Cat., xx, 3, P.G., XXXIII, 1080). Origen mentions the laying of hands, and St. Ambrose (Paulinus, Vit. Ambr., n. 28, 43, P.L, XIV, 36, 42), St. Ephraem Syrus (Greg. Nyss., De Vit. Ephr., P.G., XLVI, 848) and others used this ceremony in exorcising. The sign of the cross, that briefest and simplest way of expressing one's faith in the Crucified and invoking His Divine power, is extolled by many Fathers for its efficacy against all kinds of demoniac molestation (Lactantius, Inst., IV, 27, P.L., VI, 531 sq.; Athanasius, De Incarn. Verbi., n. 47, P.G., XXV, 180; Basil, In Isai., XI, 249, P.G., XXX, 557, Cyril of Jerusalem, Cat., XIII, 3 col. 773; Gregory Nazianzen, Carm. Adv. iram, v, 415 sq.; P.G., XXXVII, 842). The Fathers further recommend that the adjuration and accompanying prayers should be couched in the words of Holy Writ (Cyril of Jerusalem, Procat., n. 9, Col. 350; Athanasius, Ad Marcell., n. 33, P.G., XXVII, 45). The present rite of exorcism as given in the Roman Ritual fully agrees with patristic teaching and is a proof of the continuity of Catholic tradition in this matter.
(2) Baptismal exorcismAt an early age the practice was introduced into the Church of exorcising catechumens as a preparation for the Sacrament of Baptism. This did not imply that they were considered to be obsessed, like demoniacs, but merely that they were, in consequence of original sin (and of personal sins in case of adults), subject more or less to the power of the devil, whose "works" or "pomps" they were called upon to renounce, and from whose dominion the grace of baptism was about to deliver them.
Exorcism in this connection is a symbolical anticipation of one of the chief effects of the sacrament of regeneration; and since it was used in the case of children who had no personal sins, St. Augustine could appeal to it against the Pelagians as implying clearly the doctrine of original sin (Ep. cxciv, n. 46. P.L., XXXIII, 890; C. Jul. III, 8; P.L., XXXIV, 705, and elsewhere). St. Cyril of Jerusalem (Procat., 14, col. 355) gives a detailed description of baptismal exorcism, from which it appears that anointing with exorcised oil formed a part of this exorcism in the East. The only early Western witness which treats unction as part of the baptismal exorcism is that of the Arabic Canons of Hippolytus (n. 19, 29). The Exsufflatio, or out-breathing of the demon by the candidate, which was sometimes part of the ceremony, symbolized the renunciation of his works and pomps, while the Insufflatio, or in-breathing of the Holy Ghost, by ministers and assistants, symbolised the infusion of sanctifying grace by the sacrament. Most of these ancient ceremonies have been retained by the Church to this day in her rite for solemn baptism.
(3) Other ExorcismsAccording to Catholic belief demons or fallen angels retain their natural power, as intelligent beings, of acting on the material universe, and using material objects and directing material forces for their own wicked ends; and this power, which is in itself limited, and is subject, of course, to the control of Divine providence, is believed to have been allowed a wider scope for its activity in the consequence of the sin of mankind. Hence places and things as well as persons are naturally liable to diabolical infestation, within limits permitted by God, and exorcism in regard to them is nothing more that a prayer to God, in the name of His Church, to restrain this diabolical power supernaturally, and a profession of faith in His willingness to do so on behalf of His servants on earth.
The chief things formally exorcised in blessing are water, salt, oil, and these in turn are used in personal exorcisms, and in blessing or consecrating places (e.g. churches) and objects (e.g. altars, sacred vessels, church bells) connected with public worship, or intended for private devotion. Holy water, the sacramental with which the ordinary faithful are most familiar, is a mixture of exorcised water and exorcised salt; and in the prayer of blessing, God is besought to endow these material elements with a supernatural power of protecting those who use them with faith against all the attacks of the devil. This kind of indirect exorcism by means of exorcised objects is an extension of the original idea; but it introduces no new principle, and it has been used in the Church from the earliest ages.
Linkback:
https://tubagbohol.mikeligalig.com/index.php?topic=10052.0