EXPULSION
714
EXTENSION
etc.) This practice is still a very favourite one in
Belgium, though it seems directly to contravene the
spirit of many directions in the official "Cirremoniale
Episcoporum " prescribing that the Blessed Sacrament
should, when possible, be removed from the altar at
which High Mass is to be celebrated (Caer. Episc. I,
XII, 8-9). Before the Council of Trent, the abuse of
such frequent expositions, in Germany and elsewhere,
seems to have been very much checked, if not entirely
eliminated. In the sixteenth century and subse-
quently, the developments of popular devotion in this
matter have been much more restrained, and they
have always been subject to strict episcopal super-
i-ision. The practice of the Forty Hours' Devotion, and
the service now known as Benediction of the Blessed
Sacrament, are treated separately, and the reader may
be referred to the articles in question. But a good
many other varieties of services, involving Exposition
of the Blessed Sacrament for a longer or shorter
period, began to prevail in the time of St. Pliihp Xeri
and St. Charles Borromeo. Of one such variety
known as the Oratio sine interniissione, and dating at
least from 1574, a full account will be found in the
" Acta Jlediolanensis Ecclesise ". Not very long after
this, we begin to come across various religious insti-
tutes founded, with the permission of the Holy See,
for the express purpose of maintaining the perpetual
adoration of the Blessed Sacrament. See the article
Ador.^tion', Perpetual, where details are given. In
most of these cases we may assume that the Blessed
Sacrament is exposed upon the altar, though in some
religious institutes of this kind the exposition is only
continued by day.
Conditions REcrLATTNG Exposition. — The Church distinguishes between private and public Expositions of the Blessed Sacrament; and though the former practice is hardly kno\\Ti in northern Europe, or in America, it is clearly within the competence of a parish priest to permit such private exposition for any good reason of devotion, by opening the taber- nacle door and allowing the ciborium containing the Blessed Sacrament to be seen by the worshippers. There is, however, in this case no entlironing of the Blessed Sacrament or use of a monstrance. Public Exposition of the Blessed Sacrament may not take place without the permission, express or imphed, of the ordinary. In EngUsh-speaking countries, a mon- strance is almost always used when the Blessed Sacra- ment is set upon Its tlirone, but in Germany, one fre- quently sees simply the ciborium, covered of course with its veil. A certain solemnity and decorum in the matter of Hghts upon the altar, incense, music, and attendance of worsliippers is also required, and bishops are directed to refuse permission for public Exposition where these cannot be provided for.
When Mass is celebrated, or tlie Di^^ne Office re- cited, at the altar upon which the Blessed Sacrament is exposed, a new set of rubrics comes into force, biret- tas are not worn, genuflexions on both knees are made before the altar, the incense and water are not blessed, the celebrant's hand is not kissed, etc. The "Csere- moniale" seems only to contemplate the case of Mass before the Blessed Sacrament exposed during the octave of Corpus Cliristi, and at the Mass of Deposition of the Quarani' Ore, but, as already noticed, in many
Carts of Europe, local custom has made these Masses cfore the Blessed Sacrament of very common occur- rence. For the candles that ought to burn upon the altar, and for the ritual to be followed the reader may be referred to the articles Benediction, and Forty HoVRs' Devotion. Other rubrical directions dealing with such matters as the use of electric light, the ar- rangement of the throne, etc., are given in detail in manuals like that of Hartmann, or works upon Pas- toral Theology such as that of Schulze.
Giirn. in Kirchenlacikon (1713-17161. I; Thurston in The Month, June to September, 1901, and May, 1902, p. 539;
CoRBLET, Hvttoire de la Sainte Eucharistie (Paris, 18S6) ; Lupus,
De SS. Sacramenti Publico ExposUione (Li^ge, 1681); Thiers.
De V Exposition du S. Sacremenl deVAutel (Paris, 1677); R.\ible,
Der Tabemakel einst und jHzt (Freiburg. 1908), which gives
some good illustrations of German "Sacrament-houses". For
rubrical details see, for example, Schulze, Manual oj Pastoral
Theology (Milwaukee. 1906), 56-62); Va.v der Stappen, Sacra
Liturffia (Mechlin, 1903\ V, Caremoniale; SchCck, Pastoral
Theologie (Innsbruck, 1905), p. 628.
Herbert Thurston.
Expulsion. See An.^^thema; Degrad.vtion; Ex- communication; Religious Orders; Vow.
Extension (from Lat. ex-tendere, to spread out). — That material substance is not perfectlj' continuous in its structure, as it appears to our gross senses, the physi- cal sciences demonstrate. The microscope reveals pores in the most compact matter, while the permea- tion of gases and even of liquids through solids indi- cates that the densest bodies would probably present to a sufficiently penetrating eye a sponge-like struc- ture throughout. This fact, together with the difficulty of explaining how the senses can perceive extension, has led many theorists to deny its objectivity, al- though, on the other hand, the first of modern philoso- phers, Descartes, was so impressed by the universality of extension that he held it to be the very essence of matter. Kant makes extension a subjective form, an original condition of sensuous faculty which when stimulated by the sense-object stamps the impression accordingly. Others, with Leibniz, resolve matter into simple unextended points (monads), which by their agitation are supposed to produce in tis the impression of continuous extension. Others, with Boscovich (d. 1787), subtilize matter into simple forces which some hold to be " virtually ' ' extended. The .^.tomists (phys- ical and chemical) dissolve bodies into minute par- ticles or atoms (which some consider to be absolutely, others only physically, indivisible) of certain elemen- tary substances, which hitherto have defied further analysis but which may eventually turn out to be merely varying arrangements of some primordial homogeneous material, the radical constituent of the universe. The present teaching of Catholic philosophy on the subject may be summarized as follows: Exten- sion is either successive (fluent, as that of a stream and of time), or permanent. The latter may be viewed as either (a) continuous (mathematical, i. e. abstract, as a line; or physical), when the entitative or inte- grant parts into which its immediate subject, material substance, is divisible are united (perfectly or imper- fectly) throughout, e.g. a homogeneous wire; (b) con- tiguous, when the said parts are conjoined only by contact, e. g. a brick wall; (c) interrupted, when those parts are in some degree disjoined, though connected by an intermediate, e. g. a string of beads. We are here occupied with continuous extension only.
Continuous extension may be described as that property in virtue whereof the parts into which mate- rial substance is divisible are situally arranged in or- derly relation one bej-ond the other (internal and potentially local extension) and hence are naturally commensurate with the corresponding parts of the immediately environing surfaces (external and actual local extension). Consequent attributes of extension are divisibility, measurability, and impenetrability. ^^"herein precisely the essence of extension consists, is a controverted question. Probably the more general opinion is that extension radically and essentially consists in the internal distribution of the parts into which matter is divisible, and that external extension, or the correspondence of those parts to the parts of the locating surfaces, is a sequent property of essential or internal extension. Of course this does not explain extension. Some nearer approach to an explanation may be found in the opinion of a recent writer (Pecsil who makes extension consist in the expansive and co- hesive forces of matter — the former causing the said parts to spread out, the latter keeping them united.
