Diastase is a vegetable ferment which has the property of converting starchy foods into a soluble material called maltose. It is soluble in water and weak alcohol, insoluble in stronger alcohol. Its advantage, as compared with similar ferments in the saliva and pancreatic juice, is considerable, and its strength enables it to dissolve starches when present in the proportion of only 1 to 2,000. Like the above-named ferments, it acts in alkaline solution, but, unlike them, it continues to operate in acid media; hence its action is not disturbed by the gastric juice. Diastase is the peculiar substance which causes the ripening during germination of fruits and vegetables by converting their starches into dextrins and sugars. Hence fruit becomes more and more digestible as it ripens.

In prescribing diastase or malt extract it should be remembered that the ferment is precipitated and destroyed by alcohol of even moderate strength, and also by salicylic acid, which is antagonistic to it.

When malt is added to a pease pudding or other mashed vegetable, it separates the mass into a paste of cellulose and vegetable casein, with a supernatant solution of dextrin.

Williams recommends the use of malt flour with cereal foods to render them more digestible. Malt flour alone is too sweet, but, added in the proportion of one part to four or eight of oatmeal, it makes an excellent light, thin porridge for invalids.

A variety of malt extracts and malted foods are prepared for invalids, and many of them possess intrinsic value for nutrition and tonic action. They are especially useful in chronic and subacute ailments and convalescence from protracted fevers. They are beneficial in tuberculosis, caries, chronic abscess, neurasthenia, the scrofulous diathesis, typhoid fever, and to some extent they can be used as beverages to replace the stronger malt liquors, ale, beer, etc., for, according to Leeds, they always contain above 3 per cent of alcohol.

All malted foods are deficient in fats and protein. Farinaceous meal of any kind mixed with one eighth of its weight of ground malt forms a highly digestible combination. Even 20 per cent of meal can be used, and the preparation still keeps fluid (Roberts).

Kepler's Extract of Malt is given in the dose of a teaspoonful after meals in milk or soda water, or it may be spread upon any form of starchy food.

Loeflund's Malt Extract is given in doses of a dessertspoonful after meals in a gobletful of milk.

Maltine is made from three cereals - barley, wheat, and oats. It is rich in diastase. It may be added in equal part to wheat or barley flour which has been previously boiled in water, and the mixture may be used as a diluent of milk. Maltine may be taken after meals, either plain or added to cod-liver oil, coca wine, pancreatin, hypo-phosphites, etc., for use in tuberculosis and other diseases.

Hoff's Malt Extract is given in doses of a wineglassful or more with meals for adults, and one or two tablespoonfuls for children. It contains considerable diastase, a minimum of alcohol (about 2 per cent), and is said to be free from noxious ingredients. It may be drunk warmed, with a lump of sugar added, as a soothing draught to allay cough. If desirable for feeble stomachs, it may be diluted with water or soda water.

Trommer's Diastatic Extract of Malt is composed of the soluble ingredients of Canada barley malt. It is of a sirupy consistence and has a sweetish taste, which some patients object to, while many prefer it. The sweetness may be lessened or disguised by dilution with water, hot milk, brandy, whisky, or rum. It is advisable, if the stomach is feeble, to give teaspoonful doses at first, to be increased to a tablespoonful three times a day after meals.

Pancreatic extract or three to five grains of pancreatin with five grains of sodium bicarbonate may be added to a cupful of thick, well-boiled farinaceous gruel of any sort - oatmeal, cornstarch, etc. - and if kept at 100° F. for a few minutes, the mass is soon liquefied and made digestible. The hydrated starch has been converted into dextrin and sugar. There is little or no alteration produced in taste, and if starch is to be given to an infant under a year old for any purpose, it may be prepared in this manner.