Staging - Human Developmental Anatomy Center

Human Developmental Anatomy Center

Staging

     Carnegie Human
         Embryo
         Collection
     Becoming a
         Science
     Franklin P. Mall
     Exceptional
         Scientist
     Staging
     Expansion
     New Direction
     Molecular
     New Era

By 1915, Mall had attracted a small group of researchers to the fledging department, which originally occupied a suite of rooms in the anatomical laboratory at Johns Hopkins. A few years later, a new, four-story building would be built at the Hopkins Medical School, and the work at the department would expand to include other aspects of embryology. (Notable would be the pioneering tissue culture work of Margaret and Warren Lewis.) But for its first few years, the focus of the department's research was almost exclusively on Mall's embryos.

The modeling room at the Department of Embryology in 1921

The first task at hand was organizing and cataloging the collection. Ordering the embryos by age proved problematic. "It is quite apparent why it is difficult to determine in a satisfactory way the age of human embryos," Mall wrote in Year Book 13 (1914). "The time of fertilization is practically impossible to ascertain, as we do not know with certainty when ovulation takes place, and even if this were known it would still remain to be determined how soon after ovulation the sperm-cell enters the egg." He went on to provide the erroneous information that conception probably begins near a menstrual period. Obviously, there was lots to learn.