Diirer busied himself also in this period with theoretical works on art, two of which were published during his lifetime, one on geometry and perspective (1525) ;•and•one on fortification (1527). A work on human, pro. portions appeared posthumously. For a long time the artist had been suffering from termittent fever, which began to• sap hist strength as early as 1507. He is • represented In a drawing indicating the source of his dis. ease with his hand. The features are consid• erably wasted and wan and show the effect of great suffering. Diirer died suddenly. Pill*. heimer writes with great bitterness of the 'fact that his dear friend passed away without. a final farewell. He was buried at Nuremberg in the vault of his wife's family in Saint John's cemetery.
The development of Diirees style is interest, ing to trace. Throughout his work there • is apparent the constant struggle of the artist to free himself from the stiff formal ha'Wveflt}ons of the old school; to enrich his art by con scious striving for perfection of perspective and proportion. Continuous study of old 'and new forms, conscientious self-criticism and friendly intercourse with brilliant minds devell oped that power for intellectual and artistic realism which characterizes those works' on which his claim to renown is justly based.
The drawings of Diirer may be studied best at the Albertina Museum, Vienna. Good col lections are to be found also at the Berlin Mu seum and the British Museum. The rest are scattered through the museums of Germany; some are in the collections at Basel, Dresden, Florence, Milan and Oxford; numbers are in private collections. • Bibliography.-- Dfirees letters and diaries were partly published by Von Murr in (Jour, nal zur Kunstgeschichte> (Nuremberg 1785-87); by Campe (ib. 1827); Thausing (1872) • and fully in Lange and Fuhse's Wiirees 'schrift liche Nachlass> (Halle 1893). There is a great fund of separate works on the artist, of which there is a careful bibliography by Singer, H. W., Wersuch einer (Strassburg 1903). The best are by Bartsch, 'Le (Vol. VII, Vienna 1808) ; 'Phausing/2 vols., Leipzig 1884, English translation by Eaton), a scholarly work;. Wolfflin, 'Die Kunst Albrecht Dfire s) (Ber lin 1907). His prints have been published in 'The Publications of the Diirer Society) (1898-1908) ; his drawings in the Albertina by Schembrunner and Hader (Vienna 1895 et, seq.); Colvin, in 'Ninety-Three Drawings of Albrecht Darer> (London 1:!:). His engrav ings have been published by Galichon (Paris Duplessis (ib. 1877) ; Copper-en gravings by Liibke (Nuremberg 1876) and Leitscbub (ib. 1900).