Construction will begin soon on Harvard's new Science Center on the corner of Oxford and Kirkland Sts. The Center, first conceived five years ago, has had highest priority on the University's expansion schedule since 1966, but an anonymous gift of $12 million received on the eve of commencement makes it immediately possible.

President Pusey also announced that Jose Luis Sert, retiring dean of the Graduate School of Architecture and Design, will be the architect for the structure, working through his private firm of Sert, Jackson and Associates, which also designed Holyoke Center and Peabody Terrace. Sert has not yet announced plans for the design of the Science Center.

The Center is the first and biggest item in Harvard's $48.7 million Program for Harvard Science. The Program will also include buildings for biochemistry and engineering and applied physics, and additions to the astronomy facility on Observatory Hill, and the Peabody Museum of Compartive Zoology.

The Center will occupy a parking lot, the grounds of a wooden frame house and part of the new mall behind Memorial Hall. The section of the mall actually over the Kirkland Street Under-pass will remain, but the rest of the grass is likely to go.

Richard G. Leahy, assistant Dean of the Faculty explained Wednesday that "artificial differences" now separate scientific disciplines, especially biology, chemistry, and physics. Departments are segregated by buildings or floors, equipment, and techniques.

"Now when you take a chemistry course you disappear into the bowels of Mallinckrodt," said Leahy. "We want this to end. Through the right physical use of space we hope to enhance the intermingling of disciplines."

Leahy hopes that, in turn, the building will encourage the faculty to develop new courses and modes of teaching, as well as new ties with undergraduates.

Of the anonymous donor's identity, Leahy would only say that the financial source "is not an individual."