The cell Wall account for the shape of the bacterial cell and confers on its rigidity and ductility.The cell Wall cannot be seen by direct light microscope and does not stain with simple stain.it may be demonstrated by plasmolysis.when placed in a hypertonic solution,the cytoplasm loses water by osmosis and shrink, while the cell Wall retain its original shape and size,The cell Wall may also be demonstrated by micro dissection, reaction with specific antibodies, mechanical rupture of the cell, differential staining procedure or by electron microscope.bacterial cell Wall are about 10-25nm thick and account for about 20-30per cent of the dry weight of the cell.chemically the cell Wall is composed of mucopeptide scaffolding formed by n acetyl glucosamine and n acetyl muramic acid molecule alternative in chain which are cross linked by peptide chain.the interstices of this scaffolding contain other chemicals, varying in the different species.In general,the wall of gram positive bacteri have a similar chemical nature than those of gram negative bacteria.the cell Wall carries bacterial antigens l that are important in virulence and immunity.the lipopolysaccharides present on the cell Wall of gram negative bacteria account for their endo toxic activity and o antigen specificity.they were formerly known as the biovin antigen.the lps consist of three regions.region 1 is the polysaccharides portion determining o antigen specificity.region 2 is the core polysaccharides.region 3 is the glycolipid portion and is responsible for the endotoxic activities,that is pyrogenicity,lethal effect, tissue necrosis,anti complementary activity,b cell mitogenicity,immunoadjuvant property and antitumour activity.the outer most layer of the gram negative bacterial cell Wall is called the outer membrane, which contains various protien known as outer membrane,which contains various protien known as outer membrane proteins.porins which form transmembrane pores that serve as diffusion channel for small molecules.they also served as specific receptor for some bacteriophage.cell wall synthesis may be inhibited by many factors.lysosome,an enzyme normally present in many tissue fluids ,lyses susceptible bacteria by splitting the cell Wall mucopeptide link.when lysosome act on a gram positive bacterium in a hypertonic solution,a protoplast is formed, consisting of the cytoplasmic membrane and it's contents.with gram negative bacteria, the result is a spheroplast which differs from the protoplast in that some cell Wall material is retained.protoplast and spheroplast are spherical, regardless of the original shape of the bacterium.cell wall deficient form of bacteria may have a role in the persistence of certain chronic infection such as phyelonephritis.