NEW YORK, OCT. 26 -- Jack Baker, a 43-year-old senior block trader at the large investment firm Shearson Lehman Bros., roused himself from bed at 4:45 this morning, pulled on a business suit and a blue striped shirt, snapped on his gold watch and gold cuff links, and headed out in the predawn darkness from his suburban New Jersey home toward his office on Wall Street.

It was going to be another one of those days.

Baker said he has not slept through the night in two weeks. When he wakes up, he just wanders into his kitchen to sit and think. About half a dozen young traders on the Shearson stock trading desk have told him they're having the same problem, he said.

For Baker and the rest of them, Wall Street's second bloody Monday began in the same inauspicious way as last week's record stock market collapse.

Overnight, markets around the world fell into a tailspin. The Hong Kong market, reopened after a week's suspension of trading, was off more than 30 percent. London and Tokyo, too, were swamped by sellers. Baker knew even before the New York Stock Exchange opened that the selloff was bound to continue here.

He had been in the office both days over the weekend, lending what he called "moral support" to the traders and back office employes who were buried under the paper residue of last week's stock market pandemonium.

"It really has turned into a panic situation," Baker reflected shortly after noon today, sitting at his elevated module of telephone banks in the center of Shearson's brightly lit stock trading room.

Baker's troops handle trades of thousands of shares at a time for large institutional investors such as pension funds and corporations, or very wealthy individuals. They also trade huge blocks of stock for Shearson's own accounts. For days, they have been inundated with orders and on the receiving end of calls from furious losers.

"Emotionally, most people who are in this business are up for the game {but} it is amazing to watch the transformation in a very short period of time. ... You can see the anxiety on people's faces."

As Baker spoke, computer screens blinking around him showed the Dow Jones industrial average down about 120 points. Over his shoulder, on a pillar in the midst of the trading room, someone had tacked up a metal arrow pointing toward the far end of the room. Above the arrow was a sign: "To The Lifeboats."

"The difference is the pace," Baker said, comparing today's atmosphere to last Monday, when the Dow fell 508 points on the stock market's worst day in history. "Today, it's slow death."

It seemed that way all over Wall Street. In the Shearson trading room, while the market pitched steadily down amid the same heavy volume that characterized last week's frenzy, the traders called out their orders in drained voices.

Across lower Manhattan, in the 39th floor stock trading room of the large Wall Street firm Donaldson, Lufkin & Jenrette, the same wan mood prevailed. "The pain is just about the same," said Robert M. Dewey Jr., managing director of institutional stock trading, as he looked over the rows of traders under his supervision. "A little less panic is about all that's different."

"I think last week was pure shock and horror," said Eric T. Miller, the firm's chief investment officer. "Now, obviously there's still fear present and some desperation, but not as much utter amazement."

"A lot of people worked all weekend," Dewey said. "Our operations people have been here until 10 every night. People are getting worn down but they don't have much choice" about staying on the job.

The stress is beginning to exact a toll. At Shearson, Baker said he had to send one young stock trader on vacation this week even though the stock trading desk was being crushed under the weight of unprecedented volume.

"I know the symptoms," Baker said. "You watch a guy withdraw and start talking to himself."

On Thursday, Baker said, Shearson Chief Executive Peter A. Cohen came down to the trading room and delivered a 15 minute speech to the traders, emphasizing that if any of them was experiencing financial or emotional problems, Shearson would take steps to help.

"Depression has really set in," Baker said. "When it becomes a 20-hour-a-day thing, it tends to drive them right down to the lower rung on the ladder mentally. And it looks like they're never going to get out of the cellar."