At that time Mr. Pearson had lapsed into unconsciousness, and later an oxygen unit was carried into his Rockcliffe home, where he is being treated.

Until yesterday the illness had not been publicly specified, but Dr. Burton said that "the cancer has now spread to the liver." Mr. Pearson's right eye was removed in 1970, as part of an operation to remove a tumor in that area.

About a month ago he re-entered hospital for further unspecified treatment, and then he and his wife, Maryon, flew to Florida for a scheduled three-week holiday. But they returned Christmas Eve, and since then Mr. Pearson's condition has deteriorated rapidly.

The two Pearson children, Mrs. Walter Hannah of Toronto and Geoffrey, an External Affairs officer now lecturing at the University of British Columbia, were both at Mr. Pearson's home.

Mr. Pearson, who resigned as Prime Minister in 1968 after five years in office and 10 years as Liberal Party leader, was working on his memoirs - one volume has already been published - until his recent illness forced him to stop.

After his eye operation, he gave up all outside activities, including lecturing at Carleton University and follow-up work connected with his World Bank study on aid to underdeveloped countries.

The gravity of Mr. Pearson's condition was not officially made public before the arrival of his son and daughter. Since Christmas Eve, a family friend said, the deterioration has been "very rapid."

Another former Prime Minister, John Diefenbaker, who was Mr. Pearson's political adversary for many years, yesterday asked Canadians to pray for Mr. Pearson.

"I think I speak for Canadians as a whole, that their prayers should go up to Almighty God that He in His grace will allow Mr. Pearson to continue his work internationally, to which he now is giving his entire devotion."