The two faces in the middle of the page are composites of 25 boys and 25 girls, to create the “typical” student face. In modern times, this has been done digitally to interesting effects. I wonder if this is the earliest known example of such a composite.

THE AMERICAN STUDENT ACQUIRING A UNIFORM FACE: Mayor Gaynor’s Statement to That Effect Starts a Discussion — A Distinct American College Type Being Developed, Unlike the European University Man (PDF)

From July 9, 1911