FERMENTATION

a change brought in various substances, especially organic liquids, by agents called ferments, which are of two kinds: organized ferments, or living organisms, bacteria, yeasts, moulds; and unorganized fer or enzymes, or soluble chemical substances. in order to bring about f. organized ferments the organisms be alive and growing, and eertain conditions are nece ary for their growth. ‘Suitable nourishment and sufficient moisture must be present, the temperatur e must be within a certain limited range, about blood-heat, some of organisms require the presence of oxygen, while various poisonous substances, (e.g.) acids or alcohols in too quantity, or antiseptics, will kill and thus prevent f. ‘These organisms are either unicellular of protoplasm, bacteria, which multiply by fi ion of the cells; or more developed cells which multiply budding, yeasts; or still more highly developed organisms, which branch and multiply by the formation special organs, moulds. They live on nutritive substances in the liquid and out products, allied to the unorganized enzymes, which break down pi Foe ea organic pes et id eyed) Susats, into simpler y, and, (e.g.) in the making of it is caused by yeast (Saccharomyces cerevisioe) acting on solutions of sugars, or dextrin, extracted from malt, changing them into alcohol, caracid gas, and small quantities of substances which give the liquid special ] flavor. most important unorganized {is diastase, which is containe d malt, and changes starch into glucose, others are ptyalin in the saliva, pepsin in gastric juice, which have the same properties.