Bacteriological nutrient broths (and agars prepared from them) in which the digested protein is not added as peptone, but is derived from the action of enzymes such as trypsin digesting partially cooked meat in an alkaline state at 37°C. In Hartley’s broth the digestant is an alcoholic extract of porcine pancreas (Cole and Onslow’s pancreatic extract) acting on beef heart. In Horse flesh digest medium pancreatin is employed, and commercial peptone is added to the digest product. (The medium is used for heavy cultivation of haemolytic streptococci.)