[en] Some of the dialyzable products of the digestion of Micrococcus lysodeikticus cell walls by lysozyme and by a similar enzyme secreted by a Streptomyces have been isolated and their compositions determined. The two simplest substances released by both enzymes are (a) a di-saccharide of N-acetylmuramic acid-N-acetylglucosamine and (b) an N-acetylmuramic acid-N-acetylglucosamine complex. Seven peptide-acetyl-amino sugar complexes have been isolated. All seven compounds contain lysine, glutamic acid, glycine, alanine in the same molecular proportions as found in the original cell wall and a di-saccharide moiety of N-acetylmuramic acid and N-acetylglucosamine. One of the peptide-amino sugar complexes contains in addition a polysaccharide moiety [N-acetylmuramic acid-N-acetylglucosamine]10.