ZURICH, May 9 (Reuters) - A 104-year-old Australian scientist traveled to Switzerland to end his life, telling a news conference on Wednesday the nation's liberal assisted suicide laws let him commit suicide legally, in contrast to his home where it remains forbidden.

Ecologist David Goodall, who is not terminally ill, said he was ready for the end. He answered reporters questions in the Swiss city of Basel while accompanied by members of groups that help people kill themselves.

He understood that his death, planned for Thursday, would be by lethal injection, though he did not know what time or many details about the procedure. Some family members would be present, he said.

"One should be free to choose the death, when death is at an appropriate time," said Goodall, a member of the Order of Australia who wore a pullover emblazoned with the words "Aging Disgracefully."

"My abilities have been in decline over the past year or two, my eyesight over the past six years. I no longer want to continue life. I'm happy to have the chance tomorrow to end it."

Photos of Goodall: 19 PHOTOS Australian scientist David Goodall, 104, plans to kill himself with 'Swiss option' See Gallery Australian scientist David Goodall, 104, plans to kill himself with 'Swiss option' David Goodall, 104, reacts during a news conference a day before he intends to take his own life in assisted suicide, in Basel, Switzerland May 9, 2018. REUTERS/Stefan Wermuth TPX IMAGES OF THE DAY David Goodall, 104, arrives to hold a news conference a day before he intends to take his own life in assisted suicide, in Basel, Switzerland May 9, 2018. REUTERS/Stefan Wermuth David Goodall, 104, speaks during a news conference a day before he intends to take his own life in assisted suicide, in Basel, Switzerland May 9, 2018. REUTERS/Stefan Wermuth David Goodall, 104, reacts during a news conference a day before he intends to take his own life in assisted suicide, in Basel, Switzerland May 9, 2018. REUTERS/Stefan Wermuth Australian scientist David Goodall arrives in a wheelchair to hold a press conference on May 9 2018, on the eve of his assisted suicide in Basel. - 104-year-old Australian scientist David Goodall, resentful that he was forced overseas to die, is set to address the media in Switzerland on May 9, 2018, a day before he is due to end his life. He does not have a terminal illness but says his quality of life has deteriorated and that he wants to die. He was barred from seeking help to end his life in Australia, so he was forced to travel to Switzerland. (Photo by SEBASTIEN BOZON / AFP) (Photo credit should read SEBASTIEN BOZON/AFP/Getty Images) BASEL, SWITZERLAND - MAY 09: Australian botanist and academic David Goodall, who is 104 years old, holds hands with Taiwanese actress and television hostess Bowie Tsang during the filming of a documentary film about Goodall at the Basel University Botanical Gardens the day before his planned assisted suicide on May 9, 2018 in Basel, Switzerland. Goodall said he made the decision because he had no other choice, as Australia does not allow assisted suicide. Goodall is being assisted by Exit International and plans to end his life on May 10. (Photo by Sean Gallup/Getty Images) David Goodall, 104, holds a news conference a day before he intends to take his own life in assisted suicide, in Basel, Switzerland May 9, 2018. REUTERS/Stefan Wermuth David Goodall, 104, reacts during a news conference a day before he intends to take his own life in assisted suicide, in Basel, Switzerland May 9, 2018. REUTERS/Stefan Wermuth BASEL, SWITZERLAND - MAY 09: Australian botanist and academic David Goodall, who is 104 years old, tours the Basel University Botanical Gardens with three of his grandchildren and two of their partners (one grandson is pushing the wheel chair, followed by the grandson's wife) the day before his planned assisted suicide on May 9, 2018 in Basel, Switzerland. Goodall said he made the decision because he had no other choice, as Australia does not allow assisted suicide. Goodall is being assisted by Exit International and plans to end his life on May 10. (Photo by Sean Gallup/Getty Images) David Goodall, 104, arrives to hold a news conference a day before he intends to take his own life in assisted suicide, in Basel, Switzerland May 9, 2018. REUTERS/Stefan Wermuth BASEL, SWITZERLAND - MAY 07: A tram rides past buildings in the historic city center on May 7, 2018 in Basel, Switzerland. David Goodall, a 104-year-old scientist and academic from Australia, is in Basel to end his life in an assisted suicide. Goodall said he made the decision because he had no other choice. Goodall is being assisted by Exit International and plans to end his life on May 10. (Photo by Sean Gallup/Getty Images) BASEL, SWITZERLAND - MAY 09: Australian botanist and academic David Goodall, who is 104 years old, tours the Basel University Botanical Gardens with three of his grandchildren and two of their partners (one granddaughter is pushing the wheel chair, followed by one grandson's wife) the day before his planned assisted suicide on May 9, 2018 in Basel, Switzerland. Goodall said he made the decision because he had no other choice, as Australia does not allow assisted suicide. Goodall is being assisted by Exit International and plans to end his life on May 10. (Photo by Sean Gallup/Getty Images) David Goodall, 104, holds a news conference a day before he intends to take his own life in assisted suicide, in Basel, Switzerland May 9, 2018. REUTERS/Stefan Wermuth BASEL, SWITZERLAND - MAY 08: Australian scientist and academic David Goodall (R), who is 104 years old, speaks with Swiss doctor Christian Weber at the hotel where Goodall is staying two days before his planned assisted suicide on May 8, 2018 in Basel, Switzerland. Goodall said he made the decision because he had no other choice, as Australia does not allow assisted suicide. Goodall is being assisted by Exit International and plans to end his life on May 10. (Photo by Sean Gallup/Getty Images) David Goodall, 104, arrives to hold a news conference a day before he intends to take his own life in assisted suicide, in Basel, Switzerland May 9, 2018. REUTERS/Stefan Wermuth David Goodall, 104, arrives to hold a news conference a day before he intends to take his own life in assisted suicide, in Basel, Switzerland May 9, 2018. REUTERS/Stefan Wermuth David Goodall, 104, speaks during a news conference a day before he intends to take his own life in assisted suicide, in Basel, Switzerland May 9, 2018. REUTERS/Stefan Wermuth BASEL, SWITZERLAND - MAY 08: Australian scientist and academic David Goodall, who is 104 years old, speaks with Swiss doctor Christian Weber at the hotel where Goodall is staying two days before his planned assisted suicide on May 8, 2018 in Basel, Switzerland. Goodall said he made the decision because he had no other choice, as Australia does not allow assisted suicide. Goodall is being assisted by Exit International and plans to end his life on May 10. (Photo by Sean Gallup/Getty Images) BASEL, SWITZERLAND - MAY 09: Australian botanist and academic David Goodall, who is 104 years old, gets a hug from Taiwanese actress and television hostess Bowie Tsang during the filming of a documentary film about Goodall at the Basel University Botanical Gardens the day before his planned assisted suicide on May 9, 2018 in Basel, Switzerland. Goodall said he made the decision because he had no other choice, as Australia does not allow assisted suicide. Goodall is being assisted by Exit International and plans to end his life on May 10. (Photo by Sean Gallup/Getty Images) Up Next See Gallery Discover More Like This HIDE CAPTION SHOW CAPTION of SEE ALL BACK TO SLIDE

Assisted suicide has been legal in Switzerland since the 1940s, if performed by someone with no direct interest in the death. The Netherlands legalized euthanasia in 2002 for patients considered to be suffering unbearable pain with no cure.

In many countries, however, physician-assisted suicide or euthanasia are illegal.

Australia has forbidden such practices, though the state of Victoria became the first to pass an euthanasia bill last November to allow terminally ill patients to end their lives. It takes effect in June 2019.

Goodall was born in London in 1914 and moved in 1948 to Australia, where he was a lecturer at the University of Melbourne. An expert in arid shrublands, he also worked in Britain and held academic posts at U.S. universities.

While visibly straining to hear questions, Goodall answered them clearly and in detail after they were repeated with a microphone. He said he felt a "sense of pressure," given media attention on his end-of-life journey to Switzerland.

"I don't feel that anyone else's choice is involved," he said. "It's my own choice to end my life tomorrow."

Goodall had not given much thought to a last meal, as he said his culinary choices have grown more limited. He had not considered music to accompany his death, but thought Beethoven's 9th Symphony might be nice, he said, before singing a few lines.

Goodall said he is not without regrets: "There are many things I would like to do, but it's too late. I'm content to leave them undone." (Reporting by John Miller Editing by Peter Graff)

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