How did spemann separate the two cells of the embryo of a salamander in 1902?

In 1902, Hans Spemann separated the two cells of a salamander embryo using a fine hair loop to physically divide the two cells shortly after the first cleavage. This technique allowed him to observe the developmental potential of each cell. Spemann's experiment demonstrated that each cell could develop into a complete organism, supporting the concept of developmental equivalence in early embryonic cells. This work laid the foundation for future studies in developmental Biology and embryology.