John Singer Sargent, Portrait of Carolus Duran (1879)

In an altogether exceptional degree he does give us the sense that an intention and the art of carrying it out are for him one and the same thing.  In the brilliant portrait of Carolus Duran, which he was speedily and strikingly to surpass,  he gave almost the full measure of this admirable peculiarity, that perception with him is already by itself a kind of execution.  It is likewise so, of course, with many another genuine painter; but in Mr. Sargent's case the process by which the object seen resolves itself into the object pictured is extraordinarily immediate. It is as if painting were pure tact of vision, a simple matter of feeling.
--Henry James, "John S. Sargent," Harper's New Monthly Magazine, October 1887


The first work to receive general notice was his spirited portrait of Mr. Carolus Duran.  The young painter is already revealed with his personal taste and tendencies in this

graceful canvas. Based on the same science of nature, on the same logic of vision, as his master's work, it already differs not only in brushwork but in the general qualities of feeling and taste. It is conceived in a less militant and magisterial vein of style and ornament. As a rendering not only of the structure of the sitter but of his air and manner, it equals any portrait that Mr. Sargent has since done, although it may scarcely reach the pitch of bravura attained in the execution of later work.  
--R.A.M. Stevenson,, "J.S. Sargent," The Art Journal  (London 1888)

To other painters such dexterity has come, if at all, after long labor; but it was Sargent's from the first. His portrait of Carolus-Duran with which he made his debut was hailed as a masterpiece of cleverness, and so it was; but alongside of the " Girl with a Rose " that followed,           it seemed labored and academic — as if he had been hampered by his master's presence. It is the only one of his works that looks as if it might have been done bit by bit and worked over; his other canvases have the air of absolute spontaneity. There is no under- ^ painting, overpainting, or glazing, there is no heavy body color, the paint, made fluid with oil and turpentine, is brushed on exactly as it should be and left. A head is ordinarily finished in a single sitting, for the purity of the tone must not be impaired by alterations or reworking.

What desperate hard work, what struggles constantly renewed the artist has gone through that he might paint with ease, he alone knows. 

--Samule Isham, The History of American Painting (1905)

For years past Americans have repaired to his studio in the Passage Stanislus as to a shrine. His pupils are Legion, and some have rivalled their teacher. Among them is John S. Sargent, the most brilliant and perhaps most striking of American painters.

One of Sargent's greatest triumphs, by the bye, was his portrait of "Carolus," which figured inthe 1879 Salon. The rapins of the Latin quarter, never over-reverent, said that the portrait represented Carolus-Duran not as he was at the time, but as he would have wished to be.

The young artist may have flattered his model a trifle, but the resemblance was close enough. He showed us a handsome man of five and forty, tall and erect; a rugged face, of a Spanish cast, crowded by dark masses of tangled hair; a thick mustache, curling upward; eyes full of will, vivacity, and intelligence; the whole instinct with strength and character.

"Ishamel," "French Painters Chez-eux," The Illustrated American July 1890