Heart Infusion Agar is used for the cultivation of fastidious microorganisms (e.g., Vibriocholerae), to determine hemolytic reactions, as a base in carbohydrate fermentation tests, and for the mass cultivation of microorganisms in the preparation of vaccines. Beef Heart Infusion, Peptic Digest of Animal Tissue, and Pancreatic Digest of Casein provide sources of carbon, nitrogen and vitamins. Sodium Chloride supplies essential electrolytes and maintains the osmotic equilibrium. Agar is the gelifying agent.