LAS VEGAS—Sequestered in her private laboratory near Goodsprings, Celine Dion has demanded that no one disturb her until the next scent in her perfume line is complete, her manager and husband René Angelil announced Monday.

Dion inspects 300 mL of Anise hyssop essence.

"Celine has been in that lab for 27 days so far, and judging from the jasmine-smeared birthday card I received yesterday, she has no intention of taking a break any time soon," Angelil said. "She calls once a week to ask how our son is doing, but otherwise, she leaves the phone off the hook, unless she's ordering essential oils or equipment."

Angelil continued: "Celine has to replace her lab equipment quite frequently. She works so intensely that the machines burn out."

Dion, who holds doctoral degrees in botany and chemistry from the University of Montreal, has instructed her bodyguards not to allow anyone other than her 12 assistants into the lab.

"Celine built her lab outside of town so that she wouldn't be disturbed," Angelil said. "When I visit—just to make sure she's eating—she throws beakers at me. She says I destroy her concentration."

Added Angelil, "Have you ever been hit in the face with a beaker of pure essence of neroli oil?"

Angelil said he has worried about Dion ever since she announced that she would launch a new fragrance, tentatively called One Heart, as a follow-up to Celine Dion Parfums, the collection of eau de toilette, body lotion, and shower gel that she developed last year.

"Developing the first scent nearly killed her," Angelil said. "She's such a perfectionist. It was after months of non-stop work and a 46-hour stretch of not sleeping that she finally hit upon the perfect blend of fresh florals—lily, orange blossom, and exotic Tiare flower—balanced with rich amber, sheer musk, and creamy blonde woods. Why is she putting herself through this again?"

Although Dion has not been home since she began work almost a month ago, Angelil said she sporadically sends him terse e-mails.

"I get e-mails at all hours of the morning," Angelil said. "They'll say, 'Huge breakthrough...eucalyptus is showing promise, if centrifuge can hold,' or 'Discovered three new maceration techniques...patent pending.' She never responds to my e-mails, but at least I know she's alive."

"I got another one today," Angelil said. "She said, 'Closer, but still not there. Scent must be ideal for everyday use, yet sophisticated enough for special occasions.'"

Although Dion herself refused to comment, she allowed one of her assistants, molecular biologist Dr. Deborah Lasser, to speak to the press about Dion's $46 million, state-of-the-art laboratory.

"Celine's lab is a research scientist's dream—33 rooms with all the best equipment," Lasser said. "When she developed her first fragrance, Celine employed labor-intensive, 17th-century techniques like enfleurage and used jojoba carriers. But for her follow-up fragrance, she's using only the newest techniques, like hypercritical carbon-dioxide extraction and chromatographic photography, to isolate the various elements in the oils. It's a complete 180. Celine doesn't rest on her laurels."

Continued Lasser: "She pushes us to the limit, but no one works as hard as she does. I've worked both the day and night shifts, and she's always here. Every eight hours, she lies down in a hermetically sealed room to let her olfactory glands rest, but it's half an hour, two hours at most, and then she's back in the lab."

Lasser said she's amazed both by Dion's work ethic and by her "God-given talent" for dissecting and analyzing various scents without the aid of equipment.

"I've never seen anyone with such an acute olfactory sense," Lasser said. "Last week, a delivery came in. It was supposed to be an order of fresh pine needles from a white fir tree in Stockholm. Without even opening the box, Celine told the FedEx man that someone had made a mistake, and that the box contained Douglas fir needles. When we opened the box, we found out that she was right."

Earlier this year, Dion took several weekend-research trips to remote locations around the world to forage for exotic flowers.

"In February, we passed up an amazing touring opportunity so that Celine could go to Argentina and cultivate a patch of rare indigo Tillandsia diaguitensis," Angelil said. "It's really important to her that this scent be even more special than the last. I just hope she doesn't do lasting harm to her mental or physical well-being."

In a July interview with the Toronto Sun, Dion said she was confident that her new perfume would be better than her first.

"I know so much more now," Dion said. "In retrospect, I feel that using peppercorn poppy as a top note was a mistake. I'd say, also, that the amber base note seems out of place. It's too aggressive, too young and self-indulgent. Now, when I smell the bath gel, it screams, 'Look at me, see how I adapted Hobson's Isles of Sicily cold-soap method.' It doesn't have that classic, confident feel, like Chanel's blend of sandalwood, vetiver, musk, vanilla, chive, and foam of oak."

Lasser said that before Dion locked herself in her laboratory, she researched the work of 18th-century perfumer Francois Coty, the man widely recognized as the first great perfumer of the modern age.

"Celine knew that getting into Coty's head would help her with her own work," Lasser said. "She said, 'It's not just about the fragrance. It's also about the bottle and presentation.' I guess that's why those men showed up today and asked where they should build the glass-blowing oven."