fermentation. When juices of fruits are fermented for 

 making wine, when cooked or uncooked meat or vegetables 

 get spoilt, when milk gets sour, when curd of milk is ready 

 for churning, when cheese is getting ripe, special microbes 

 are generated. These are either useful or harmless microbes. 

 But it is by similar processes of fermentation, souring, or 

 spoiling, that germs capable of producing diseases in plants, 

 animals and man, are generated. It is said, that in the 

 battle-field 16 soldiers die from enteric fever and other 

 pathogenic diseases to every one killed by a bullet. A know- 

 ledge of microbes helpful and inimical to agriculture is thus 

 of very great importance. 



1,283. Enzymes. True ferments must be distinguished 

 from enzymes which are elaborated from protoplasm and 

 which have the power of making food substances soluble. 

 Many foods are insoluble in water, and as plants including 

 microbes are not able to utilise food except from solutions, the 

 food substances utilised by plants are first decomposed and 

 then absorbed. Absorption of food substances in the alimen- 

 tary canals of animals, similarly takes place after decomposi- 

 tion effected by enzymes. To distinguish them from microbes, 

 enzymes are called unorganized ferments. Enzymes are 

 insoluble in alcohol but soluble in water and they must be in 

 solution to be able to do their work of decomposing food 

 substances. In the saliva, for instance, there is an enzyme 

 which dissolves starch converting it into sugar. In seeds also 

 there is an enzyme, called diastase, which is capaple of con- 

 verting starch into sugar. There is another enzyme called 

 pepsin, in the stomachs of higher animals, which has the 

 power of dissolving meat in the presence of an acid. In the 

 intestine there is an enzyme which is able to dissolve 

 meat in the presence of an alkali. Enzymes do not diminish 

 or increase in amount (like microbes) in doing their work. 

 They do their work best in the presence of moisture at a 

 temperature of about 98 F. Heating to the boiling point 



