"A lot of schools, particularly after the First World War, began moving toward a modernist curriculum and away from the idea of such work," said Al Gury, chairman of the academy's painting department and an academy graduate himself.
"They frankly saw [the casts] as old-fashioned and not conducive to personal expression."
But the academy never wavered from its commitment to putting students through the rigors of studying the masterpieces of ancient Greece and Rome, in particular - the proportions, anatomy, play of light across surfaces.
Michelangelo's David looms over the cast hall now, as it has for more than a century. Nearby is the second-century B.C. Winged Victory of Samothrace. Both have been restored.
There are 165 casts in the academy's collection, most dating from the 19th and very early 20th centuries, and generally not open to public viewing.
When the academy first opened in a building on Chestnut Street, between 10th and 11th Streets, it was quickly stocked with 17 casts of statues, 25 busts, six feet and hands from the studio of the Louvre's cast maker, according to research by retired academy archivist Cheryl Leibold.
All were destroyed by a fire that wrecked the building in 1845.
Most of the casts currently in use were made in the last years of the 19th century, when it was still possible to make molds from the original works of art. Many art institutions and schools took advantage of the practice and filled exhibition spaces and instruction halls with plaster replicas of antique works.
Over the last century, however, most of those pieces have been destroyed or placed in darkest storage.
There are stirrings of change again. Some art schools are showing renewed interest in cast drawing, Gury said, which could lend new life to the academy's collection and its academic tradition.
Beyond that, regardless of fashion, at least some students seem to fall in love with the practice.
Just last year, he said, a former academy student held a memorial service for his wife of 50 years in the academy's cast hall. The couple had met there during the first-year required course, drawing casts side by side.
"There is a romanticism about the cast hall," said Gury. "Students understand that it's an important part of their heritage."
Contact culture writer Stephan Salisbury at 215-854-5594 or firstname.lastname@example.org.