When we consider that _Prince Igor_ was written piecemeal, in intervals snatched between medical commissions, boards of examination, lectures, and laboratory work, we marvel to find it so astonishingly cohesive, so delightfully fresh. Borodin describes the difficulties he had to contend with in a letter to an intimate friend. "In winter," he says, "I can only compose when I am too unwell to give my lectures. So my friends, reversing the usual custom, never say to me, 'I hope you are well' but 'I do hope you are ill.' At Christmas I had influenza, so I stayed at home and wrote the Thanksgiving Chorus in the last act of _Igor_." Borodin took his work very seriously, as we might expect from a scientist. He had access to every document bearing on the period of his opera, and he received from Hunfalvi, the celebrated traveller, a number of melodies collected among the tribes of Central Asia which he employed in the music allotted to the Polovtsy. But there is nothing of meticulous pedantry apparent in Borodin's work. He has drawn a vivid picture of the past, a worthy pendant to the historical paintings of his contemporary Vasnietsov, who has reconstructed mediæval Russia with such astonishing force and realism. Borodin modelled his opera upon Glinka's _Russlan and Liudmilla_ rather than on Dargomijsky's _The Stone Guest_. He had his own personal creed as regards operatic form. "Recitative does not conform to my temperament," he says, "although according to some critics I do not handle it badly. I am far more attracted to melody and cantilena. I am more and more drawn to definite and concrete forms. In opera, as in decorative art, minutiæ are out of place. Bold outlines only are necessary. All should be clear and fit for practical performance from the vocal and instrumental standpoints. The voices should take the first place; the orchestra the second."