The first experiments on Ascidian and Sea Urchin eggs fertilization

Abstract

In 1845 Karl Ernst von Baer made the first experiments on artificial fertilization of ascidian and sea urchin eggs in Cornigliano near Genoa (Italy). These studies were continued in Venice and Trieste and the results were published in 1847 as a preliminary note. von Baer considered the eggs of sea urchins to be an excellent material for embryological investigations. He described the formation of the fertilization envelope, the nuclear migration to the center of the egg, and the nuclear divisions which determined the pattern of the cytoplasmic divisions. These observations led to the conclusion that all nuclei of larval and adult tissues are derived from the nucleus of the fertilized egg. The 1847 preliminary note did not include figures, but von Baer illustrated his findings with a pencil drawing that is published here for the first time.