blastoderm: the germinal membrane from which the organs of the embryo are formed. Explanation of Terms Used in Entomology John. B. Smith He it was who introduced the terms Keimhaut (blastoderm) and Keimblatt (germ-layer).
Child Study. Child study, also called paidology or experimental pedagogy, was the attempt to apply the methods of modern science to the investigation of children in order to discover the laws of normal child development.
Cohort study. A cohort study is similar in concept to the experimental study. In a cohort study the epidemiologist records whether each study participant is exposed or not, and then tracks the participants to see if they develop the disease of interest.