The painting depicts Dr. Samuel D. Gross, a seventy-year-old professor dressed in a black frock coat, lecturing a group of Jefferson Medical College students.

Included among the group is a self-portrait of Eakins, who is seen at the left-hand side of the painting, next to the tunnel railing, with a white cuffed sleeve sketching or writing.

It is assumed that the patient depicted in The Gross Clinic was a teenage boy, although the exposed body is not entirely discernible as male or female; the painting is shocking for both the odd presentation of this figure and the matter-of-fact goriness of the procedure.

When it was eventually displayed in Ward One of the U.S. Army Post Hospital, a critic for the New York Tribune wrote that it was: ...one of the most powerful, horrible, yet fascinating pictures that has been painted anywhere in this century...but the more one praises it, the more one must condemn its admission to a gallery where men and women of weak nerves must be compelled to look at it, for not to look at it is impossible.Another critic, writing in 1885, said: It is characterized by so many excellent artistic qualities, that one regrets that the work as a whole fails to satisfy.

The monochromatic tone of the composition is, perhaps, intentional, in order to concentrate the effect on the bloody thigh and the crimson finger of the operating professor.

In similar paintings by Ribera, Regnault,[4] and other artists of the horrible, as vivid a result is obtained without sacrificing the light and color in the other parts of the picture; and the effect, while no less intense, is, therefore, less startling and loud.

The critic for Philadelphia's The Evening Telegraph, who may have been aware of the personal politics involved in the advisory group of artists who rejected it, wrote: There is nothing so fine in the American section of the Art Department of the Exhibition, and it is a great pity that the squeamishness of the Selecting Committee compelled the artist to find a place for it in the United States Hospital building.

Modern scholars have suggested that the painting may be read in terms of castration anxiety and fantasies of mastery over the body (e.g. Michael Fried), and that it documents Eakins's ambivalence about representing sex difference (e.g. Jennifer Doyle).

"[3] In 2006, in response to the impending sale of this painting, The New York Times published a "close reading" which sketches some of the different critical perspectives on this work of art.

The Denver-based Anschutz collection purchased Cowboys in the Badlands at a May 22, 2003 auction at Christie's New York for $5,383,500, which was the previous record for an Eakins painting.

[12] In 1929, Susan Macdowell Eakins, the artist's widow, wrote a letter of complaint regarding the "fancy red light" that had falsified the painting's intended tones.

[14] In 1961, at the request of Jefferson Medical College, the Philadelphia Museum of Art (PMA) undertook another restoration, under conservator Theodor Siegl.

Definition of parts, including Eakins' self-portrayal, was restored, using as reference an ink wash copy of the painting made by the artist, as well as a photograph taken by the Metropolitan Museum of Art previous to the Medical College's changes in 1917.