Alton Toussaint Lemon, 84, formerly of Mt Airy, a retired social worker and the plaintiff in a 1971 landmark court case that challenged state aid to religious schools, died May 4 of Alzheimer’s disease at his home in Rydal Park in Jenkintown.

Mr. Lemon had filed a lawsuit that questioned the legality of a 1968 Pennsylvania law permitting religious schools to receive reimbursement for certain expenses as long as they were linked to secular subjects taught in public schools.

In his opinion in Lemon v. Kurtzman on June 28, 1971, Chief Justice Warren Burger ruled that the law violated the First Amendment, which prohibits government establishment of religion, and created the “Lemon test,” requiring courts to consider “whether the challenged government practice has a secular purpose, whether the primary effect is to advance or inhibit religion, and whether it fosters excessive government entanglement with religion.”

Burger said the Pennsylvania law failed the entanglement provision of the Lemon test.

A longtime Mt. Airy resident, Mr. Lemon was born in McDonough, Ga., and raised in Atlanta, where he attended public schools through the 10th grade. He graduated from a private high school in Lawrenceville, Va., and earned a bachelor’s degree in mathematics from Morehouse College.

He served in the Army for two years, then worked for a time as a civilian for the Department of Defense at Aberdeen Proving Grounds in Maryland.

After deciding to become a social worker, he completed a master’s degree in social work at the University of Pennsylvania and began a long career of public service and community organizing.

Before retiring in 1987, Mr. Lemon had worked for Bristol Township Community Action, North City Congress, Germantown Settlement, the Department of Housing and Urban Development and the Department of Energy.

In retirement, he served as president of the Greater Philadelphia Chapter of the Morehouse College Alumni Association and president of the Philadelphia Ethical Society. He was a lifetime member of the ACLU, the NAACP, and West Mt.Airy Neighbors.

He is survived by his wife of 63 years, the former Augusta Ramsey; a son, Anthony George, and two grandchildren.

A memorial service was held June 8 at Rydal Park. Memorial donations may be made to the Alzheimer’s Association, Box 96011, Washington, DC 20090. – WF