The chapter discusses the extraction of bacterial components using phenol/water emulsions, focusing on two methods: cold emulsion and warm homogenized phenol/water mixtures. The cold emulsion method involves treating gram-negative bacteria with a phenol/water emulsion in the cold, which rapidly releases somatic glycoproteins (mainly O-antigens) into the aqueous phase. The warm homogenized mixture method involves treating bacteria with a heated phenol/water mixture, which dissolves both glycoproteins and nucleoproteins, resulting in protein-free polysaccharides in the aqueous phase and proteins in the phenol phase. The chapter also details the purification and analysis of these extracted components, including their antigenic properties and potential applications. The authors note that the glycoproteins from gram-negative bacteria are antigenic for rabbits, and the purified, protein-free polysaccharides are also antigenic, suggesting their potential use in immunization.The chapter discusses the extraction of bacterial components using phenol/water emulsions, focusing on two methods: cold emulsion and warm homogenized phenol/water mixtures. The cold emulsion method involves treating gram-negative bacteria with a phenol/water emulsion in the cold, which rapidly releases somatic glycoproteins (mainly O-antigens) into the aqueous phase. The warm homogenized mixture method involves treating bacteria with a heated phenol/water mixture, which dissolves both glycoproteins and nucleoproteins, resulting in protein-free polysaccharides in the aqueous phase and proteins in the phenol phase. The chapter also details the purification and analysis of these extracted components, including their antigenic properties and potential applications. The authors note that the glycoproteins from gram-negative bacteria are antigenic for rabbits, and the purified, protein-free polysaccharides are also antigenic, suggesting their potential use in immunization.