THE CAREER soldiers are still there, and the doctors and the technicians. But they no longer operate with what used to be called military efficiency. And they no longer bully the Arlo Guthries of the world.

The austere fortress on Whitehall Street, for years an American Bastille in the eyes of activists, has fallen to the times.

Twenty of us from New Rochelle arrived there one recent morning, courtesy of Local Board Number Nine, to see and be seen and, perhaps, reclassified. Our group was an ethnic reflection of our city: Italians and Irish from the South End, by the Sound, Blacks out of the battered center city, and Jews, clutching medical reports and X-rays, from the North End.

"What have you got?" asked Larry Stillman of John Margolis, en route to the induction center.

"Two allergists' reports and notes from a doctor and a shrink. How about you?"

"I just have a note from a shrink."

"That's enough. I just wanted to make sure, myself."

An hour later, at the center, John Larga, who was down at Whitehall for his third physical, asked an officer how long a drafted man has to serve. "Two years," replied the officer. Larga looked surprised. "Good," he said, "I thought it was three or four years."

John Larga had not thought to bring a note.

The processing of potential draftees is a lengthy and confused business. The induction center has eight floors, bridged by rickety stairs and an ancient, attendant-operated elevator. Registrants are required to proceed from room to room and floor to floor in seemingly random order.

The men who direct the nervous human flow-soldiers and doctors-are almost uniformly young. Many of them, perhaps half, are black. They function like workers on an assembly line at an automobile plant; without enthusiasm, without complaint.

Sergeant Petti, a small man who was trying hard to grow a moustache, administered the intelligence test to most of the New Rochelle group. "This is a four-part test," he said in a monotone, reciting from memory words that the rest of us followed in our test books. "There are arithmetic questions, questions dealing with verbal skills, visual questions, and puzzle questions."

When he finished reciting the instructions he warned us not to try to flunk the test because they had ways of finding out and, anyway, the results would go in our permanent records and we might not be able to get jobs.

"Are you threatening us?" someone asked.

Sergeant Petti looked at him and said in a tired voice, "I'm not threatening anyone. I've got 101 days left and I'm just trying to do my job."