Autolytic Enzymes as a Source of Error in the Preparation and Study of Gram-negative Cell Walls

SUMMARY: The cell wall of Salmonella gallinarum, like that of other Gram-negative organisms, was found to contain a separate continuous rigid mucopolymer layer. This structure was rapidly broken down by the cell's own enzymes during wall preparation when suitable precaution against this action was not taken. Possible errors in the interpretation of cell-wall structure, deriving from this and other causes, are discussed.