The mysterious illness of President Jacques Chirac, who has been hospitalized for five days, triggered a scramble among his potential successors this week and focused criticism on the secrecy that historically surrounds the health of France's top leader.

Chirac, 72, was admitted to Val de Grace military hospital in Paris on Friday after complaining of a severe headache and troubled vision. The next day, Prime Minister Dominique de Villepin said the president had experienced "a small vascular accident." The term "vascular" refers to blood and lymph vessels.

On Monday, a statement from Chirac's office said he had suffered "a small-sized hematoma." A hematoma is a tumor-like collection of blood outside a blood vessel.

Chirac's office gave a generally upbeat assessment Wednesday. The president was conducting business from his hospital room, including a 45-minute telephone conversation Tuesday with German Chancellor Gerhard Schroeder, according to an official in the office. Chirac was expected to be released from the hospital by Friday, the official said, after which a decision would be made on whether he would travel to New York next week for a U.N. summit.

But the absence of medical details -- which have been closely guarded by the president's doctors and aides -- has medical experts speculating on the severity of the ailment. They said it could range from a minor broken blood vessel to a stroke.

The information vacuum was quickly filled by rumor, fueled by the political jockeying of the top two contenders to replace Chirac -- de Villepin and Interior Minister Nicolas Sarkozy.

On Wednesday, de Villepin, who is presenting himself as a figure of continuity, ran the cabinet meeting, the first that Chirac has missed since assuming office in 1995. Sarkozy, who advocates a clean break with the past for the party that all three men belong to -- the Union for a Popular Movement -- delivered a speech calling for major economic reforms.

"Since last Friday, we've known that Chirac will not run for another mandate," said Dominique Moisi, deputy director of the French Institute of International Relations. "It seemed absurd that he should do so anyway, but now the age factor has been multiplied by the health factor, and that makes it totally impossible, and that's why the fight has erupted between his successors."

Nicole Bacharan, an analyst at the Institute for Political Studies in Paris, said that "politically, Chirac's in a bunker and cornered." Bacharan cited the recent defeat of Paris's bid to host the 2012 Olympics, France's rejection of the proposed European Union constitution in a May referendum and Chirac's opposition to the U.S.-led war in Iraq as key factors behind his political slide.

"He's never been as low in the polls," she said. "I'm not sure the French public realizes how weak he is abroad, too, and how the position on Iraq weakened the weight France has on international affairs. He's weak inside and out, at home and abroad. He's just trying to survive until the end of his term" in 2007.

Political commentators said unanswered questions about Chirac's medical condition recalled the secrecy that surrounded the health of Presidents Georges Pompidou and Francois Mitterrand. Both men died of illnesses that afflicted them while in office but were hidden from the public under France's strict laws protecting medical confidentiality.

"In France, we practice a cult of secrecy which would have made the Kremlin proud," Le Monde newspaper said in an editorial on Tuesday.

Chirac's office would not comment on his political woes. But the official there, who spoke on condition of anonymity in line with office policy, defended the handling of medical information. "We did not hide anything, because there's nothing to hide," the official said. "We communicated everything as quickly and as transparently as possible."

President Jacques Chirac, 72, was admitted to the hospital Friday.