uch to quicken the public taste.
Diderot pleaded for a return to nature in the theatre; for a bourgeois
drama, domestic tragedy and serious comedy, touched with pathos,
studied from real life, and inspired by a moral purpose; for the
presentation on the stage of "conditions" rather than individual
types--that is, of character as modified by social environments and
the habits which they produce. He maintained that the actor should
rather possess than be possessed by his theme, should be the master
rather than the slave of his sensibility.

The examples of dramatic art which Diderot gave in his own plays,
the _Pere de Famille_ and the _Fils Naturel_, are poor affectations
of a style supposed to be natural, and are patently doctrinaire in
their design, laboured developments of a moral thesis. One piece in
which he paints himself, _Est-il bon? Est-il mechant?_ and this alone,
falls little short of being admirable, and yet it fails of true
success.

A coherent system of thought cannot be found in Diderot's writings,
but they are pregnant with ideas. He is deist, pantheist, atheist;
he is a materialist--one, however, who conceives matter not as inert,
but quick with force. He is edifying and sincere in his morality;
and presently his morals become the doctrines of an anarchical licence.
All the ideas of his age struggle within him, and are never reduced
to unity or harmony; light is never separate in his nature from heat,
and light and warmth together give rise to thoughts which are
sometimes the anticipations of scientific genius; he almost leaps
forward to some of the conclusions of Darwin. His great powers and
his incessant energy were not directed to worldly prosperity. Diderot
was never rich. The Empress Catherine of Russia magnificently
purchased his library, and entrusted him with the books, as her
librarian, providing a salary which to him was wealth. He travelled
to St. Petersburg to thank her in person for her generous and delicate
gift. But her imperial generosity was not greater than his own; he
was always ready to lavish the treasures of his knowledge and thought
in the service of others; no small fragment of his work was a free
gift to his friends, and passed under their name; Holbach and Raynal
were among his debtors.

His correspondence presents a vivid image of the man and of the group
of philosophers to which he belonged; the letters addressed to Mlle.
Volland, to whom he was devotedly attached during ma