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.