Reeling under a flood of undergraduate students for the first time in its usually staid history, the Harvard Summer School ended a hectic week of registration with an estimated total of over 4000 enrollees.

Official figures have not yet been released, and the complicated and varied classes of registrants will have to be broken down before an exact picture of the Harvard population this summer can be given. But it is evidently a different picture than in past years, when Summer School attendance consisted mainly of teachers, degree seekers, and dropped Freshmen.

Three Classifications

Those who registered have been divided into three classes and are filed as such in the little frame house where the enlarged Summer School still has its home. The classes are undergraduates, Radcliffe students, and "others". Among the last species are all non-Harvard students and girls who are taking courses here for the summer only.

The undergraduate class, of course, is the biggest reason for the phenomenal registration. Under the accelerated program, well over half the student body returned to Cambridge instead of taking summer vacations, and 703 members of the Class of '46 are also in the Houses as the first installment of what promises to be the largest Freshmen Class in history.

Summer School activities went into full swing over the past weekend, with two dances and an outing, and will continue to move ahead with many lectures and more dances coming at the end of this week.