hen the medieval Latin 'sortiarius' (not 'sortitor' as in Richardson),
supplied another word, the French 'sorcier', and thus our English
'sorcerer' (originally the "caster of lots"), then 'witch' gradually was
confined to the hag, or female practiser of these arts, while 'sorcerer'
was applied to the male.

New necessities, new evolutions of society into more complex conditions,
evoke new words; which come forth, because they are required now; but
did not formerly exist, because they were not required in the period
preceding. For example, in Greece so long as the poet sang his own
verses 'singer' ({Greek: aoidos}) sufficiently expressed the double
function; such a 'singer' was Homer, and such Homer describes Demodocus,
the bard of the Phaeacians; that double function, in fact, not being in
his time contemplated as double, but each part of it so naturally
completing the other, that no second word was required. When, however,
in the division of labour one made the verses which another chaunted,
then 'poet' or 'maker', a word unknown in the Homeric age, arose. In
like manner, when 'physicians' were the only natural philosophers, the
word covered this meaning as well as that other which it still retains;
but when the investigation of nature and natural causes detached itself
from the art of healing, became an independent study of itself, the
name 'physician' remained to that which was as the stock and stem of the
art, while the new offshoot sought out a new name for itself.

Another motive to the invention of new words, is the desire thereby to
cut short lengthy{122} explanations, tedious circuits of language.
Science is often an immense gainer by words, which say singly what it
would have taken whole sentences otherwise to have said. Thus
'isothermal' is quite of modern invention; but what a long story it
would be to tell the meaning of '_isothermal_ lines', all which is
summed up in and saved by the word. We have long had the word
'assimilation' in our dictionaries; 'dissimilation' has not yet found
its way into them, but it speedily will. It will appear first, if it has
not already appeared, in our books on language{123}. I express myself
with this confidence, because the advance of philological enquiry has
rendered it almost a matter of necessity that we should possess a word
to designate a certain process, and no other word would designate it at
all so well. There is a process of 'assimilation' going on very
extensive