Increasingly, white students are enrolling at the nation's 120 historically black colleges and universities. In the past quarter-century, the number of white students at these campuses has risen 65 percent, from 21,000 to nearly 35,000 - an increase driven partly by court orders aimed at desegregation and partly by interest in programs the schools offer. Most of the influx of white students has come at public institutions, which receive funding from federal and state governments. Such colleges are pressured to increase their white enrollment - even as affirmative action requirements at some other universities are waning.