WHAT is there about a sun-backed plot of crabgrass called Harvard Yard that summer after summer draws people from 50 states, 77 countries, and 415 colleges to the banks of a smelly river? What transformation does the summer solstice effect to make "staying-in-Cambridge" the thing to do for at least one, and maybe even two or three summers of one's Harvard career?

There are, of course, the academic reasons. Despite constant criticism from other universities, Harvard will allow its students academic credit only for courses taken at Harvard Summer School, so if there is a reason for a Harvard student to take summer courses, he will be taking them here. Accelerating, making up deficiencies, enduring the martyrdom of 34 hours a week of Chem 20--these are some things that keep Harvard students at Harvard Summer School. And for the others, whose own colleges may or may not have summer schools but undoubtedly accept Harvard credits, Harvard dis--well, Harvard.

But that is obviously not the only, or even the main reason for record enrollments year after year. For those who are under no pressure to earn money, summer school is one alternative among several, like a job, or travel, or loafing (which, statistics show, almost non one does--or at least not without listing it under "travel.") It keeps you away from home but lets you live in a sociable place where the friends--and the action--are familiar. Taking a course or two makes the summer respectable, regardless of whatever else keeps you in Cambridge.

The Mystique

And underlying it all is the mystique of summer-in-Cambridge. Ask anyone who says he know, and he will conjure up images of effortless pick-ups by day--all those sweet little girls who come to Cambridge to get a Harvard man of their very own--and endless parties by night in the enclaves -- Putnam Square, Harvard Street, Porter Square--where Harvard and Radcliffe students tend to cluster. Like all such legends, some of the Cambridge summer-time stories are true and some are not--or, more accurately, they are more true for some than for others.

Who are those 4800 people who arrive in the Square the day before the Fourth of July? They are, first of all, those who can afford to come. Summer School itself is not overly expensive: registration costs $25, each half-course is $165 (the usual load is two half-courses), and the fee for auditing varies from $20 to $110 a course, depending on the rest of the program. But there are living expenses, too: almost all the non-Radcliffe girls, and many of the non-Harvard boys, live in the dorms, where room and board is $270.

Thomas E. Crooks, Director of the Summer School, calls the tuition "the lowest of any school, of our quality that I know of," but to that must be added the opportunity cost. If you go to summer school you can probably not manage a full-time job, and scholarship students are required to earn money during the summer. Crooks would like the Financial Aid Office to interpret that requirement more flexibly, but the Summer School itself controls no scholarship funds.

Aside from the financial profile are the statistics. Last summer there were 321 Harvard undergraduates, 98 Cliffies, and 952 Harvard graduate students. There were 1852 undergraduates from other colleges, mostly north-eastern liberal arts schools; 1301 non-Harvard graduate students; 77 high school seniors; and 196 other people "neither working toward nor possessing and degree."

And beyond that are the legends again. Ask a summer school veteran what the "summies" are like and you will get a studiedly smirking grimace and--depending on his sensibilities--either some variation on "not quite the calibre" or a hasty disclaimer like "Well, I didn't actually see too much of the summer school people." "It's funny," one Cliffie said typically, "but everyone I met in my courses was Harvard or Radcliffe."

Summer school in fact seems to evoke all the Harvard-Radcliffe sense of community that is missing the rest of the year. But it is community in a negative and at times rather ugly sense, bringing to the surface a kind of Harvard snobbery that either hurts or greatly amuses those others who come to Cambridge looking for Harvard. At the beginning of last summer, some clever entrepreneur sold "I Go Here in the Winter" buttons to those who could furnish appropriate proof, but there are subtler ways--an abbreviation dropped here, a bit of history recalled there, a nickname spoken ever so casually in the Yard--to make the point, and everyone becomes adept at the game.

The reaction to the "summies" is not difficult to understand. Certainly not all the girls are dumb--Wellesley sends probably the largest contingent other than Radcliffe--and not all of them, tease there hair, wear too much makeup, speak in raucous Brooklyn accents, or sport tight Harvard sweat-shirts. But you notice those. "You don't realize how attached you are to this place," a Harvard junior explained, "until you see it being raped." A Cliffie commented, "During the winter you share Cambridge with 5000 of your won kind, so you don't feel terribly close to it. But in the summer you're one of the happy few fighting off the invaders."

The same Harvard students who speak of the "summies" with scorn admit to having joined the "competition for the bunnies"--as one put it--with relish. (Actually, the boys out-numbered the girls last year by more than 400.) Director Crooks, who views the scene with ironic humor from his seventh-floor office in Holyoke Center, remarks that "Some Harvard students wear those 'winter' buttons and keep to themselves, but some plunge right in and enjoy it."

But again--as with the myth of summer-time Cambridge--the "summie" stercotype can be misleading. Summer school admission is far from rigorous, which is the way the administration likes it, but still, as Crooks points out, "we have to produce a student body that the faculty is happy to work with." And to an extent which would probably surprise most "winter" people, he has.

Visiting faculty members often tell him that their summer school course was "the best class I ever taught." Regular Harvard faculty members are occasionally more skeptical -- "any teacher who likes out and sees a class with a high school junior and a Jesuit Father won't know quite what he's talking to," Crooks comments. But Harvard Faculty members too are often pleasantly surprised. One Harvard professor, who taught a popular summer school course with about two-thirds non-Harvard enrollment, recalled that, "I was prepared for a disappointment, but it turned out to be some of the most rewarding teaching I've ever done."

If you wanted to maintain the Harvard snobbery, you could explain the "summies" performance by theorizing that during the summer Harvard-Radcliffe under-achieves, while the "summies" over-achieves. But you do not have to put it in those terms. The summer school students are impressed by Harvard, and by being at Harvard, and so take the school and themselves seriously. They study, they work hard (one Cliffie who shared a dormitory suite with three "summies" remembers that they were surprised by and even disapproving of her erratic study habits) and they do well--69 per cent of the grades last summer were A's and B's, and 71 per cent of the students received at least one honors grade.