Hamburger-Hamilton Staging Series (1951)

In 1951 Viktor Hamburger [4] and Howard Hamilton created an embryonic staging series from a combination of photographs and drawings from other researchers. The Hamburger?Hamilton stages are a sequence of images depicting 46 chronological stages in chick [5] development. The images begin with a fertilized egg [6] and end with a fully developed chick [5]. The Hamburger-Hamilton staging series was produced in order to replace a previous chick [5] staging series created in 1900. The earlier attempt lacked specific details and staged the chick [5] embryo by using only morphological characteristics. As chicks were, and still remain, model organisms for experimental embryology [7], it was important to create a staging series with descriptions for determining the approximate age of a developing chick [5] embryo.