ALL who are interested in the progress of biology will learn with deep regret of the sudden death of Dr. Franklin P. Mall, of Johns Hopkins University, at the age of fifty-five. It was chiefly owing to his precepts and example that, in little more than a score of years, a complete revolution was wrought in the anatomical departments attached to medical schools throughout the length and breadth of the United States. Dissecting-rooms were changed from places in which routine teaching and perfunctory investigation were carried on to laboratories where exact methods were applied to the elucidation of definite problems. Prof. Mall was thirty-one years of age when he returned in 1893 from a long course of study under the late Prof. His, of Leipzig, to become the first professor of anatomy in Johns Hopkins University, Baltimore. He designed his own department, selecting a slimly built, cheap, brick construction, and settled down with his students to combine study with research. He devoted himself to embryological and microscopic investigations, reconstructing his results in the exact model methods practised by Prof. His. His writings cover the whole field of embryology, every contribution representing a permanent addition to knowledge. His pupils left him to fill the various chairs of anatomy as they fell vacant, and carried to their new departments the methods and spirit they had imbibed from Franklin Mall. He took a leading-part in the foundation of the excellent journals which have been established in the United States for the publication of anatomical investigations—the American Journal of Anatomy, the Anatomical Record, and the Journal of Morphology. He pursued the study of human embryology in a more systematic manner than has ever been accomplished by any other man.