Under the influence of his teacher Haeckel, Driesch had tested the mechanistic embryological theories of another of Haeckel's students, Wilhelm Roux. Driesch studied sea urchin embryos, and found that when he separated the two cells of the embryo after the first cell-division, each developed into a complete sea urchin. This was contrary to his expectation that each cell would develop into the corresponding half of the animal, a prediction based on Wilhelm Roux's earlier work with frog embryos. This also happened at the four-cell stage: entire larvae ensued from each of the four cells, albeit smaller than usual. By 1885 Driesch's experiments on the sea urchin embryo showed that it was even possible to shuffle the blastomeres of the early embryo without affecting the resulting larva.
