the clavier-toccata in C minor; but Bach does not choose to weary the
hearer and weaken the impression of breadth he has already made here.
Instead, he expands this restatement of the introduction, and makes its
harmonies deliberately return to the fundamental key, and thus in an
astonishingly short time the toccata is brought to a close with the utmost
effect of climax and finality. The same grasp of all the possible meanings
of an artistic device shows itself in his treatment of the other features
of toccata form. With his variety of proportion and flow he has no need to
break off the fugue like earlier composers: but all the old devices by
which the division into sections was managed are turned to account by him,
and almost every toccata has its own scheme of contrasted movements, always
based on the old natural idea of the growth of an organized music from a
chaos of extemporization.

If this is Bach's treatment of a comparatively small and specialized
art-form, it is obviously impossible to reduce the scantiest account of the
rest of his work into practical limits here, nor is there as yet a
sufficient body of accepted criticism of Bach for such an account to carry
further conviction than an expression of individual opinion. Fortunately,
however, Bach was constantly re-arranging his own compositions; indeed he
evidently regards adaptability to fresh environment as the test of his
finest work: and we cannot do better than review the evidence thus given to
us,--evidence which only Beethoven's sketch-books surpass in significance.

2. The successful transplanting of a work of art to a fresh environment is
obviously a convincing test of our definitions of the art-forms concerned,
if only we take care to distinguish between the alterations produced by the
change of environment and those that imply the composer's dissatisfaction
with the original version. In Bach's case this seldom causes much
difficulty; his methods of adaptation are so logical and so varied as to
form a scheme of musical morphology with all the interest and none of the
imperfections of the geological record; and the few cases in which a work
owes its changes to the need for improvement as well as adaptation cause no
confusion, but rather form a link between the pure adaptations and the
numerous revisions of his favourite works without change of medium. There
is, for example, no difficulty in separating the element of corrective
criticism from that of t