t they were placed on the list of
European dyeing substances. Catechu is fixed by oxidation of the
colouring principle, catechin, on the cloth after dyeing or printing;
and treated thus it yields a variety of durable tints of drabs, browns
and olives with different mordants (see DYEING). The principal
consumption of catechu occurs in the preparation of fibrous substances
exposed to water, such as fishing-lines and nets, and for colouring
stout canvas used for covering boxes and portmanteaus under the name of
tanned canvas. Black catechu is official in most pharmacopoeias except
that of Great Britain, in which pale catechu is the official drug. The
actions and uses of the two are similar, but black catechu is the more
powerful. The dose is from five to twenty grains. The _pulvis catechu
compositus_ contains catechu and kino, and may be given in doses twice
as large as those named. The drug has the actions and uses of tannic
acid, but owing to the relative insolubility of catechu-tannic acid, it
is more valuable than ordinary tannic acid in diarrhoea, dysentery and
intestinal haemorrhage.

CATECHUMEN (Lat. _catechumenus_, Gr. [Greek: katechoumenos], instructed,
from [Greek: katechein], to teach orally), an ecclesiastical term
applied to those receiving instruction in the principles of the
Christian religion with a view to baptism. As soon as Christianity
became a missionary religion, it was found necessary to make
arrangements for giving instruction to new converts. At the beginning
the Apostles themselves seem to have undertaken this duty, and the
instruction was apparently given after baptism, for in Acts ii. 41, 42,
we are told that "they that gladly received the word were baptized ...
and they continued stedfastly in the Apostles' teaching." There are two
instances in the New Testament where reference is made to individual
instruction in this technical sense. Luke (i. 4) in dedicating the third
Gospel to Theophilus tells him that his aim in writing the book was
"that thou mightest have certainty in the things in which thou has been
instructed" ([Greek: katechethes]) and we are told that Apollos was
instructed ([Greek: katechemenos]) "in the way of the Lord" (Acts xviii.
25).

With the development of Christianity the instruction became more
definite and formal. It is probable that the duty of instructing
converts was assigned to "the teachers," who are ranked by Paul
immediately after the Apostles and prophets