Aprile, who lives for love as Paracelsus for knowledge, is not to be identified with Shelley, but he has unmistakable Shelleyan traits, and the dreamy pageant of his imaginary creations might stand for a summary review of Shelley's work.
Had Shelley lived, he might have come nearer than any one else to fulfilling the rounded and complete ideal of which Paracelsus and Aprile were dissevered halves: the greater part of his actual achievement belonged, Browning evidently thought, to the category of those dazzling but imperfectly objective visions which he ascribes to his Aprile.

But Shelley--the poet of _Alastor_, the passionate "lover of Love," was yet the fittest embodiment of that other finer spiritual energy which Paracelsus in his Faustian passion for knowledge had ruthlessly put from him.

Sixteen years later, Browning was to define in memorable words what he held to be the "noblest and predominating characteristic of Shelley"-- viz., "his simultaneous perception of Power and Love in the Absolute and of Beauty and Good in the concrete, while he throws, from his poet's station between both, swifter, subtler, and more numerous films for the connection of each with each than have been thrown by any modern artificer of whom I have knowledge." This divining and glorifying power it is that Browning ascribes to Love; the lack of it is in his conception the tragic flaw which brings to the ground the superbly gifted genius of Paracelsus.

This genuine and original tragic motive is not worked out with uniform power; his degeneration, his failures, are painted with the uncertain hand of one little acquainted with either.

But all the splendour of a young imagination, charged with the passion for truth and for beauty, glows in the pictures of the great moments in Paracelsus's career,--the scene in the quiet Wuerzburg garden, where he conquers the doubts of Festus and Michal by the magnificent assurance of his faith in his divine calling; and that in the hospital cell at Salzburg, where his fading mind anticipates at the point of death the clearness of immortal vision as he lays bare the conquered secret of the world.
That Paracelsian secret of the world was for Browning doubtless the truth, though he never again expounded it so boldly.