Eakins taught painting at the Pennsylvania Academy of Fine Arts. Jeff Rosenheim, a curator in the Department of Photographs at the Metropolitan Museum of Art in New York (where an exhibit of Eakins' work is showing until fall) says, "As a painter, the camera was one of many different tools that Eakins demanded his students master to train the eye to see what is truly there. He had great belief in preparatory work, such as working on a cadaver to really understand the difference between muscles and tendons and bones."

The teacher himself was no stranger to nudity. Eakins stripped and turned his butt to the camera. He had a picture taken of himself sitting naked on a horse. In perhaps the most striking photo, Eakins stands naked holding a nude woman limp in his arms. It's likely she was a model. Eakins encouraged his female students to strip for each other, but the only coed willing to do it for the camera was a girl named Susan Macdowell. She had a long back and pleasant breasts. Eakins eventually married her. The other female subjects in his photographs were likely professional models, who sometimes wore masks to hide their faces.

Eakins had no trouble getting his male students to go buff. These boys were photographed wrestling naked in the dirt or playing the pipes as if they were Pan. Eakins was an early supporter of Eadweard Muybridge, and together the two made motion study "strobe" photographs of naked men walking and running and jumping.

Although Philadelphia was the city of "brotherly love," and Eakins knew Walt Whitman, art historian John Esten (author of the just published "Thomas Eakins: The Absolute Male") says there is no gay subtext to Eakins' work. "I don't think that has anything to do with it. Many of the students became friends and remained very close to him until he died." Eakins expert Darrel Sewell, retiring curator of American art at the Philadelphia Museum of Art (where the Eakins show originated) says, "There's a whole homosexual thing where people say, 'Well, Eakins took photographs of naked men therefore he must be gay.' That's a whole idea that appeared in the 1970s. There is no contemporary evidence that he was. But homosexuality didn't have very much of a stigma attached in the 1870s, 1880s."

As for the nudes, Eakins took more photographs of naked men and women than he actually painted. One of his most famous paintings is "Swimming," done in 1884-85. It depicts six naked young men and a retriever swimming on a sunny day. The painting is in the American realism style of the time -- a little impressionistic, but nothing like what was going on in Paris. The colors are sober. This is not Tom and Huck taking a dip naked.

"Eakins painted 'Swimming' for the new head of the committee of instruction at the academy," Sewell says. "The painting was Eakins' summary of what he thinks academic art was all about. It was also a painting of naked male students at the academy. It was hard to imagine the head of the board of the academy hanging a picture of naked academy students in his living room."

In those days, men and women studied in separate classrooms and the male artists painted male models who were completely naked, while the females painted men wearing loincloths. The president of the art academy, James Claghorn, believed that the sight of an American penis would violate these girls' "maidenly delicacy." Furthermore, they would lose their "treasure of chaste and delicate thoughts."

According to the Random House Historical Dictionary of American Slang, "bullshit" was first uttered as a synonym for "nonsense" in 1866, so it's very likely that's what Thomas Eakins thought Claghorn was full of. Eakins was an alpha male who was coarse and belligerent and often arrogant.

So in the autumn of 1885, when Thomas Eakins stood in a classroom full of prim maidens behind their easels and whipped down the male model's loincloth, he probably gave no warning at all. The man just presented an American penis to the girls. A simple penis. Just how simple, we'll never know. Was it circumcised? Long or fat? How violated did those maidens feel? Based on later female students' reactions to Eakins' presentation of male nudity in the 1890s, some of those 1885 women were hospitalized. Some assumed that Eakins had now become their husband.