Dr. Bell also conducted a research career and was the primary investigator in a national pulmonary embolism research study.

He played an instrumental role in the improvement in the treatment of thrombotic thrombocytopenia purpura — better known as TTP — a rare blood disorder that causes microscopic clots to form in small blood vessels throughout the body.

"As we say in medicine, disease occurs after 5 p.m. and on weekends, so when Bill was conducting this research on TTP, he put a cot in his office on which he would sleep so he could capture the patients," said Dr. Spivak.

"He was an expert on bleeding and clotting. He was a real scholar and a prolific writer on this subject. He knew it all," he said.

Dr. Bell also was something of an eccentric who was seldom without 20 pens in his pocket, said his wife.

"Bill was very gregarious but also very eccentric. He loved going to Memorial Stadium to see Notre Dame play football," recalled Dr. Spivak with a laugh. "I looked down, and there was Bill sitting on the Notre Dame bench with a towel over his head."

Dr. Bell enjoyed playing golf, reading and assembling slide shows from his world travels.

"Bill was also a master chef and no one knew it until he had the whole division to his house for dinner one night," said Dr. Spivak.

Dr. Bell was a communicant of the Roman Catholic Cathedral of Mary Our Queen, 5200 N. Charles St., where a Mass of Christian burial will be offered at 11 a.m. Friday.

In addition to his wife, Dr. Bell is survived by two sons, Dr. William R. Bell III of Baltimore and George H. Bell of Gurnee, Ill.; and a daughter, Elizabeth Bell Gerber of Baltimore.