Thomas W. Langfitt, 78, a retired Philadelphia neurosurgeon and former chief executive of the Pew Charitable Trusts, one of the world's wealthiest and, for years, most secretive philanthropies, died Aug. 7 at his home in Wynnewood, Pa.

He had miliary tuberculosis, a spreading of tuberculosis bacteria throughout the body.

Dr. Langfitt was president of the Pew trusts from 1987 to 1994 and chief executive of the Glenmede Trust Co., which manages the trusts' investment portfolio, from 1987 to 1995.

The trusts' assets were valued at $4.5 billion as of June, and officials are planning to give away $204 million in the coming year.

The Pew trusts, seven in all, derive their funds from the children of Sun Oil Co. founder Joseph N. Pew. The heirs started the trusts in 1948 and for three decades doled out tens of millions of dollars to education, arts, environmental, health care and religious organizations.

Donations were typically anonymous, part of the family's core religious belief that good deeds are their own reward. The organization was guarded about inquiries into its operation, which became suspect to outsiders as it accrued billions.

After the death of the Pew children, the trusts' board recognized the need for more transparency and began to make public its annual reports. Trust officials also expanded their support for work in public policy issues, including global warming, campaign finance reform and immunization programs for poor children.

Dr. Langfitt, chairman of neurosurgery at the University of Pennsylvania hospital, had a major role in the transition after joining the board in 1980. Among policy issues, his concerns included improving the foster care system and providing access to pre-kindergarten for poor children.

"Pew intends to make a major effort to help our disadvantaged population," he told the New York Times in 1990. That "might surprise some people accustomed to thinking of the old Pew as reactionary and secretive in its early years."

Under his watch, he brought aboard staff members from a variety of backgrounds, among them Rebecca Rimel, a nurse, who succeeded him as president and CEO of the trusts. She said the charity of the early 1980s was "very much a division within a bank. Tom's vision was to be a world-class organization serving the public interest."

Dr. Langfitt called on the trusts' staff members to talk with ministers, among others with leadership roles in minority communities, to learn how the trusts could best help.

Thomas William Langfitt was born April 20, 1927, in Clarksburg, W.Va., where his father was a general surgeon. He was a 1949 graduate of Princeton University and a 1953 graduate of the Johns Hopkins University medical school.

He joined the University of Pennsylvania faculty in the 1960s and was chairman of neurosurgery from 1968 to 1987. He became involved with the Pew trusts as an adviser on their health-related grants.

He wrote or contributed to more than 200 professional publications. He sat on a variety of medical advisory and editorial boards as well as the boards of New York Life Insurance Co. and what is now GlaxoSmithKline, a pharmaceutical company.

A son, Thomas Langfitt Jr., died in 1979.

Survivors include his wife of 53 years, Carolyn Payne Langfitt of Wynnewood; three sons, David Langfitt of Bryn Mawr, Pa., John Langfitt of Rochester, N.Y., and Frank Langfitt of Washington; a brother; a sister; and eight grandchildren.

Thomas Langfitt, a neurosurgeon, headed the Pew Charitable Trusts from 1987 to 1994.