Joseph Barcroft, a fellow of King's College, Cambridge, professor of Physiology in Cambridge University, and this fall the Dunham lecturer at Harvard, will speak on "The Constancy of the Internal Environment" this afternoon at 5 o'clock at the Harvard Medical School Amphitheatre, Building C.

Dr. Barcroft's topic for his series of lectures is "Some Features in the Architecture of Function." The opening one, on Monday, was entitled "Integrative Adaptation", on Friday he will discuss "The Principle of Antagonism"; and on Monday, "Stores of Material."

The E. K. Dunham lectureship for the promotion of the Medical Sciences was founded in memory of Dr. E. K. Dunham in 1923. Among the useful purposes for which the Foundation was established was that of binding closer "the bonds of fellowship and understanding between students and investigators in this and foreign countries." The lectures, which are given annually, are "free and open to the faculty and students of the Harvard Medical School and College, and other interested professional persons who may profit by them."