The President of the Palestine Authority, Mr Yasser Arafat, and his entourage have persistently dismissed speculation that he is suffering from poor health, although he has appeared to be ill during recent public appearances.
Observing a persistent tremble in Mr Arafat's lower lip during a joint press conference with the US Secretary of State, Ms Madeleine Albright, on Saturday, an Israeli specialist suggested that the Palestinian leader was afflicted by Parkinson's disease, possibly in the early stages.
This correspondent, who met Mr Arafat both before and after his 1992 plane crash in the Libyan desert, has seen a dramatic deterioration in terms of mental agility, memory, comprehension, and use of English - learned late in life.
This would suggest an exacerbation of likely neurological damage from the plane crash or from the blood clot on the brain on which Jordanian doctors operated a year after the accident. A reliable source in Germany said Mr Arafat may have spent a day in a private clinic during a recent official visit to the country.
At the end of September Mr Arafat apparently experienced a fainting fit while attending an Arab League Foreign Ministers meeting in Cairo. His personal physician, Dr Ahmad Tibi, tried to explain away this event by saying Mr Arafat suffered from the "normal ailments" of a man of 68. But some of Mr Arafat's closest collaborators have not been convinced by such statements.
It was reported last week in the Arabic daily, al-Hayat, published in London, that Mr Arafat's security chiefs, Mr Jibril Rajoub and Mr Muhammad Dahlan, have begun to plan for the succession and perhaps even for a coup.
The fact that Mr Dahlan was in Washington recently encouraged speculation that he was seeking US approval of a future major role for him.
The aim of the security chiefs would be to outflank the politicians who are in line to succeed. These are Mr Mahmud Abbas ("Abu Mazen"), secretary of the executive committee of the PLO, and Mr Ahmad Qurei, speaker of the Palestinian Legislative Council.
While "Abu Mazen" is the second most powerful personage in the leadership, he has neither Mr Arafat's stature as liberation leader nor his grasp of PLO financial and administrative affairs.