Only less beautiful than Browning's pictures of spiritual childhood are his pictures of spiritual maturity and old age. The lyric simplicity, the naïve intensity which bear a David, a Pippa, a Pompilia without effort into the region of the highest spiritual vision, appealed less fully to his imagination than the more complex and embarrassed processes through which riper minds forge their way towards the completed insight of a Rabbi ben Ezra. In this sense, the great song of David has a counterpart in the subtle dramatic study of the Arab physician Karshish. He also is startled into discovery by a unique experience. But where David is lifted on and on by a continuous tide of illuminating thought, perfectly new and strange, but to which nothing in him opposes the semblance of resistance, Karshish feels only a mysterious attraction, which he hardly confesses, and which all the intellectual habits and convictions of a life given up to study and thought seem to gainsay. No touch of worldly motive belongs to either. The shepherd-boy is not more single-souled than this devoted "picker up of learning's crumbs," who makes nothing of perilous and toilsome journeys for the sake of his art, who is threatened by hungry wild beasts, stripped and beaten by robbers, arrested as a spy. At every step his quick scrutiny is rewarded by the discovery of some new drug, mineral, or herb,--"things of price"--"blue flowering borage, the Aleppo sort," or "Judaea's gum-tragacanth." But Karshish has much of the temper of Browning himself: these technicalities are the garb of a deep underlying mysticism. This man's flesh so admirably made by God is yet but the earthly prison for "that puff of vapour from his mouth, man's soul." The case of Lazarus, though at once, as a matter of course, referred to the recognised medical categories, yet strangely puzzles and arrests him, with a fascination that will not be put by. This abstracted docile man of perfect physical vigour, who heeds the approach of the Roman avenger as he would the passing of a woman with gourds by the way, and is yet no fool, who seems apathetic and yet loves the very brutes and the flowers of the field,--compels his scrutiny, as a phenomenon of soul, and it is with the eye of a psychological idealist rather than of a physician that he interprets him:--