The Biography of Specimen "09.04.1954, 3.4 mm" from the "Blechschmidt Collection of Human Embryos" at Göttingen University with a Special Focus on the Production and Usage of Enlarged 3D Replicas of Embryos in the Anatomical Research on Human Embryos.

The "Blechschmidt Collection of Human Embryos" housed at the Anatomical Institute of Göttingen University (Germany) is an important historical collection of human embryo specimens whose history dates back up to the mid-1940s. It is named after its founder Prof. Erich Blechschmidt (1904-1992). A 2-year research project was conducted from 2017 to 2019 with the aim of clarifying the provenience of the human embryo specimens collected by Blechschmidt. This project not only has provided information on the origin of the specimens but, additionally, led to the discovery of photographic documents illustrating the process by which Blechschmidt built the enlarged 3-dimensional replicas of human embryos that are shown in a dedicated exhibition hall in the basement of the Anatomical Institute. Here, we report on an embryo from the Blechschmidt collection whose biography as a microscopical specimen as well as a source for objects of Blechschmidt's collection of 3-dimensional replicas of human embryos is documented by letters, lab-books, and photographs. Our report is complemented by a short historical review on the production and usage of enlarged 3-dimensional replicas in research on the anatomy of human embryo.