Harvard Law School dean emeritus Erwin N. Griswold, hailed by President Johnson as one of the nation's foremost lawyers, was sworn in as Solicitor General yesterday in Washington.

"The people of the United States are a very fortunate client," Johnson said at the White House ceremony.

As solicitor general, Griswold will represent the government in cases argued before the Supreme Court. His nomination was aproved by the Senate on October 12 in a unanimous voice vote. He succeeds Thurgood Marshall, who earlier this month became the first Negro Supreme Court Justice.

Johnson said yesterday, "We are living through an era of revolution in human rights, and historical reversal of the old ways of injustice and intolerance." To America's lasting credit, he added, it is a revolution of law within the law.

He said the recent conspiracy convictions stemming from the slaying of three civil rights workers in Mississippi were part of this continuing revolution.

"In every triumph of justice all good people are the victors," the President said. "The responsibility of seeking and the challenge of winning these triumphs are America's charge to it's Solicitor General."

A. James Casner, associate dean, will be acting dean of the Law School while Griswold's successor is being selected. President Pusey has asked the Law School Faculty to submit their personal recommendations to him for Griswold's successor.

Griswold leaves the Law School after 21 years as dean. His tenure saw the construction of five new dormitories, the admission of women students, the development of International Legal Studies, and the elimination of course requirements for second and third-year students.

Griswold is no stranger to the office he now heads. In 1929, he graduated at the head of his class from the Law School, where he also edited the Law Review. For the next five years, he was a staff lawyer in the Solicitor General's office where he won a measure of fame arguing complicated tax cases before the Supreme Court.

In 1934, he returned to Harvard as a professor specializing in taxation. In 1946, he succeeded James M. Landis as dean.

Currently, he is a member of the Association of American Law Schools and a past vice president of the American Academy of Arts and Sciences.

President Pusey said of the appointment, "It's an indication of great respect. The office is an honor to the dean and to Harvard."