The Edman or phenylisothiocyanate degradation (1) has been employed for the determination of the primary structures of peptides and proteins for approximately three decades. The relative simplicity of the method and its high efficiency in the sequential removal of amino acid residues from the amino terminus of a peptide or protein has resulted in a widespread popularity and usage. In spite of the full automatization of the procedure by Edman and Begg in the nineteen sixties (2), the manual version of the sequential amino acid degradation still remains a very realistic and efficient alternative.