But the source close to the administration said the president returned home after 11 p.m. that night and was too tired to come to work the next day.

The president called Carnesale Wednesday evening and informed the provost he would be taking a medical leave of absence on his doctors' orders, according to Carnesale.

At last night's event in the Fogg Art Museum, Angelica Rudenstine expressed her family's appreciation for the concern extended to the president since the announcement of Rudenstine's medical leave of absence on Monday.

"There has been a tremendous outpouring of concern and understanding from many people that has touched us both," the guest quoted Angelica Rudenstine as saying.

Angelica Rudenstine interjected her personal remarks as she read a prepared letter from the president to approximately 150 invited guests and officials, the source said.

"I want to send a brief word of greeting to all of you who are gathered together on this important occasion," the president's letter says. "I greatly regret that I am unable to be with you. I have looked forward to this conference for many months, and I am fully with you in spirit."

The president's letter also announced that Harvard's new Center for Latin American Studies will be named after David Rockefeller '63, who has given a multi-million dollar donation to the center