OF ALL 20th century artistic movements, German Expressionism is the most diffuse and the hardest to define. Germany's 300 years of political fragmentation encouraged the development of the arts in provincial cities, rather than in a single center. In the first two decades of this century, the Second Reich's self-deluding optimism provoked artists all over Germany into a stated rejection of bourgeois culture. Die Brucke (The Bridge), a group of young artists united by their opposition to contemporary standards of taste and by their desire for a new emotional intensity in art, coalesced at Dresden in 1905. Their manifesto read:

Everyone who with directness and authenticity conveys that which drives him to create, belongs to us.

The exhibit of Expressionist prints now at the Fogg is ample evidence that this broadly worded statement did not force die Brucke's members into a single style. Gauguin's influence is very strong in Erich Heckel's woodcuts. Ludwig Kirchner, the leader of the group, learned about composition from Matisse (as Dodo Reclining shows). And one of Kirchner's later woodcuts, Dr. Bauer, demonstrates his debt to Picasso.

For a time even the strongly individual Emil Nolde aligned himself with die Brucke. Nolde's sensitivity to his medium was extraordinary, and he controlled the purely formal aspects of his work more successfully than any other member of the group. At the same time, his woodcuts have a directness and an emotional intensity rarely equalled. His haunting Prophet, with its subtle interplay of light and shade, is the high point of the show.

World War I and its bitter aftermath brought forth a new art in Germany. George Grosz's work, which has its roots in the Berlin Dada movement, attacks postwar German society with a viciousness that spares neither the Prussian military nor the lowest member of the Lumpenproletariat. Otto Dix's caricatures are equally bitter -- Dix spares not even himself. The differences between Nolde's and Dix's self-portraits illuminate the difference between the moods of pre and post-war Germany. Nolde's is brooding and mystical, with a hint of secrets yet to be revealed. Dix turns the full intensity of his cruelly precise line on himself and reveals the face of a man who believed George Grosz when he wrote:

Men are pigs. Talk about ethics is humbug, meant only for the stupid. Life has no meaning other than to satisfy one's appetite for food and women. There is no soul.