SUBSTITUTE.(The Talk of the Town)(college faculty labor disputes)

Even under normal circumstances, with the magnolias and the cherry trees in full bloom, it would have been tough last week for Columbia students to drag themselves to class, but, as luck would have it, hundreds of them were additionally hampered by a little bit of a labor situation--a graduate teaching assistants' strike that left them without instructors. Still, whether from curiosity or duty, a small number of them managed to amble into Kate Isard's Masterpieces of Western Art class, last Wednesday, knowing that they would not find Isard there. Instead, they found Robert Harrist, a professor of Chinese art and the director of the Art Humanities program, who began explaining the procedure for finishing the semester without a teacher.

Harrist, a short, trim man in his fifties with round glasses and a round face, was standing in front of a giant screen. As he spoke, Rousseau's painting "The Forest in Winter at Sunset" was projected onto his navy blazer. He squinted. Grades, he assured the students, would still be given out, and there would be a final exam. As latecomers filed in, Harrist began taking questions, walking genially among the desks.

Some students, it became clear, seemed to resent the fact that another teacher, Lynn Catterson, had been brought in to take over. Catterson, a resolute-looking summer-session instructor in her late forties, sat silently in the corner behind a small desk. "If I chose to skip the final exam, would I fail the class?" a young man in back asked.

"Well, that's something I wanted to be very clear about with the dean, and things are still up in the air," Harrist said. "We don't know what's going to happen, but, yes, your grade will be affected by your performance on the exam."

"I feel I'm being put in a difficult position," another student, with slick hair and a pressed blue oxford, said. He was stretched out on the windowsill. "You're forcing me to side with the administration when I want to support my teacher." Students shuffled in their seats.

The strike is the culmination of a long struggle between the graduate students and the university over the right to unionize. The university is taking the hard ...