mum_, has been
given to the law established by the council of Trent and subsequent
papal constitutions. There is a further distinction between the written
law, _jus scriptum_, laws made by the councils or popes, which are to be
found in the collections, and the unwritten law, _jus non scriptum_, a
body of practical rules arising rather from natural equity and from
custom than from formal laws; with this is connected the customary law.
In the Church, as in other societies, it has happened that the unwritten
customary law has undergone a gradual diminution in importance, as a
consequence of centralization and the accumulation of written laws;
nowadays it need not be reckoned with, save in cases where local customs
are involved. The common law is that which is intended to regulate the
whole body; special or local law is that which is concerned with certain
districts or certain categories of persons, by derogation from or
addition to the common law.

Sources.

By the _sources_ or authors of the canon law are meant the authorities
from which it is derived; they must obviously be of such a nature as to
be binding upon the whole religious body, or at least upon a specified
portion of it. In the highest rank must be placed Christ and the
Apostles, whose dispositions for the constitution and government of the
Church are contained in the New Testament, completed by tradition; for
the Church did not accept the disciplinary and ritual provisions of the
Old Testament as binding upon her (see Acts xi., xv.). To the apostles
succeeded the episcopal body, with its chief the bishop of Rome, the
successor of St. Peter, whose legislative and disciplinary power, by a
process of centralization, underwent a slow but uninterrupted
development. It is then to the episcopate, assembled in ecumenical
council, and to its chief, that the function of legislating for the
whole Church belongs; the inferior authorities, local councils or
isolated bishops and prelates, can only make special laws or statutes,
valid only for that part of the Church under their jurisdiction. Most of
the canons, however, which constitute the ancient law, and notably those
which appear in the _Decretum_ of Gratian, emanate from local councils,
or even from individual bishops; they have found a place in the common
law because the collections of canons, of which they formed the most,
notable part, have been everywhere adopted.

Having made these general observations, we