When the Advisory Committee on Shareholder Responsibility held an open meeting last month to discuss investments in South Africa, nearly one-third of the 30 speakers at the forum were Law School students. Considering that law students account for less than one-tenth of Harvard's student population, the turnout was noteworthy.

But Law School denizens haven't limited their activity to the apartheid issue. Tuesday night, in the middle of a blizzard that shut down the entire Boston area. 70 of them attended an introductory meeting of the Harvard-affiliated Legal Aid Bureau. Another 25 students called the bureau, which gives free legal aid to the poor, to say that they could not attend the meeting.

Activism is clearly on the rise at the Law School, following a trend some observers say has affected undergraduate campuses in many parts of the country. Students here explain the apparent increase in concern for social and political issues as a reaction to the federal budget cuts and general conservatism of the Reagan Administration. But most are quick to add that activity at Harvard does not yet indicate a strong push to the Left In fact, students say that the Law School continues to encourage conformity and point graduates toward traditional corporate careers.

Regardless of nationwide trends, the Legal Aid Bureau has enjoyed its best year in 13, says president Terry Friedberg. One hundred and twenty students applied for positions last year alone, and Friedberg adds. "We're well on our way to topping that this year."

Friedberg attributes the rise in applications to two causes students concern for poor people who can no longer receive free legal service from the federal government and the desire to get clinical experience in addition to classwork John T. Harding, operations officer for Harvard Defenders, another growing legal aid society, agrees that the current popularity of clinical education has attracted students to part-time public service work.

In another area, the Harvard Lawyers' Guild, a broad-ranging progressive legal organization, has increased its membership from 10 to 100 in the past two years, according to Thomas M. Stern, a member of the Guild's steering committee. Although only about half of the Guild's members are active. Stern says. "Two years ago. I wouldn't have believed it could have happened at the Law School."

Perhaps the most interesting development has been a surge in pledges for Student-Funded Fellowships, a program that Treasurer James F. Simon calls "a voluntary redistribution of earnings." The fellowships are funded by students' summer earnings, which are given to other students so they can practice public interest law over the summer. Simmons reports that pledges topped $21,000 this year, the most in the program's seven-year history.

James D. Vorenberg '49, dean of the Law School, calls the pledges "very significant," considering the current tight economy and the large tuition increases scheduled for next year.

Most students agree that the Reagan Administration's policies have been at least partially responsible for building membership rolls at liberal organizations. "There are more issues to get involved in this year," says Gail B. Ruderman, a first-year student. "Two years ago, nothing happened in the world."

Administrators and several student leaders point out that better management of student organizations * also be fostering expansion. "I think a lot of the changes have less to do with students interest than with who is running the program," says Harding of the Harvard Defenders.

One broad point of agreement further qualifies the trend toward activism: students apparently have not shifted their political views to the left. Instead, students and administrators say that rejuvinated collective activity reflects new methods, not new thinking.

"A few years ago, students supported things passively now people who care are doing something about it," says Norma L. Villarreal, president of the Law School Council. The council, which serves as the school's student governing body, also sponsors a free tax clinic for low-income and elderly tax-payers.

Villarreal cautions that despite more student activity, only a small proportion of the school's population participates in progressive extra-curricular programs. She adds that the Law School remains "pretty conservative on the whole."

More specifically, student leaders question the commitment of law students who join their organizations. "It's hard to judge whether there's any real commitment there." Harding said. "Some times you see more activism, but then you see everyone headed for Wall Street firms."

Though Law School placement officials observe no appreciable change in the number of graduates going into public sector jobs. Villarreal says that activism will have a long-term impact. "I think it's good because it makes people multi-faceted." she points out. "I will probably work for a firm, but I have a strong commitment to classes that will not be my clients, and I will try to help those people," she explains.