The Biochemical Differentiation of Bacteria*

The Gram Stain

“…It is impossible to compile a table which will give characteristics applicable to all organisms. For instance, the organisms in the genus Neisseria are usually classified as gram negative, but their physiological reactions are more like those of the gram posi-tive group (7,127). Thus, table 1 applies to organisms in general but does not necessarily apply to specific organisms or strains.…”

“…Correlation of gram reaction with physiological characteristics*t Gram positive cells are more resistant to digestive enzymes such as trypsin (22), pepsin (127), pancreatic juice (43). Gram positive cells are more resistant to lysis or death from the action of alkalies (116,117,127).…”