In a letter to the college community, President Fergusson announced that Professor of Political Science Glen Johnson, a member of the Vassar faculty since 1964, woud serve as acting president in the fall term of 1997.  A member of the board of the Ford Foundation, Fergusson planned to spend most of her sabbatical representing the foundation in Africa and Asia.  "The pleasure and intellectual engagement of traveling on behalf of Ford," she said, "is that one has a chance to meet both with Presidents and senior Ministers of countries and with people very much at the grass roots level, including those who live at the very bottom of the economic ladder....  The travel is often not comfortable by Western standards, but very memorable.... There is no doubt," she added, "that Professor Johnson will do a superb job as Acting President in my absence."     The Miscellany News