THIS month Dartmouth heads into the homestretch of its 187th year. Only seventeen days of classes remain for the seniors, who begin comprehensives on May 21; and the rest of the students have only one additional week of classes before they come face to face with final exams. This period of scholastic reckoning carries through until early June, when Commencement weekend begins with Class Day on Friday, June 8. Immediately after Commencement Day, June 10, a full week of alumni reunions, Hanover Holiday and Alumni Council meetings runs from June 11 to 17. Then the Summer Solstice arrives and, in the minds of the alumni, if not in any other way, the Dartmouth professors and administrators can lie under the cork trees and smell the flowers.