DIASTASE, or AMYLASE, a substance belonging to the group of enzymes and believed to be itself a mixture of several simple enzymes. It is found in barley, oats and other plants and also in animal tissues. When in solution it possesses the prop erty of causing starch to break up at the temperature of 156° F., transforming it first into dextrin and then into maltose. It is ob tained by digesting in a mixture of three parts of water and one of alcohol, at a tem perature of 113° F., a certain quantity of ger minated barley ground and dried in the open air, and then putting the whole under pressure and filtering out the liquid. Such extracts evaporated at a low temperature in a vacuum to a thick syrupy condition are known in com merce as *malt extracts.* Diastase is solid, white and soluble in water and diluted alcohol, but insoluble in strong alcohol. If 200 parts of fecula be mixed with 1,000 parts of water and a portion of diastase be added and the mixture kept at a temperature of about F., the starch is converted gradually into dextrin and then into grape sugar. The action of the
diastase is threefold, liquefaction of the starch, hydrolizing it into dextrin and then hydrolizing the dextrin into maltose. This triple function is regarded as proving the composite nature of the diastase. The action of diastase is prevented by acids, alkalis and some salts, but not by alco hol or ether. A solution of diastase becomes acid and loses its power on starch. The ac tion of the diastase of germinating barley is important in brewing, distilling and in the bak ing industry. The composition of diastase has not been exactly determined. It is, however, an albuminoid substance. A body having the power of converting starch into sugar exists in saliva and is known as ptyalin. It is also an albuminoid and is probably analogous to diastase in its composition. Diastase is used in the man ufacture of dextrin (q.v.). As malt extract it has a limited use in laundries for removing starch from stiffened fabrics before they are laundered.