324 AGRICULTURAL CHEMISTRY 



poisonous, and death is often caused by these toxic 

 bodies. Modern methods of sanitation are based upon 

 the destruction of disease-producing organisms. 



448. Beneficial Organisms. While many diseases are 

 caused by micro-organisms, not all micro organisms or 

 bacteria are injurious. In nearly all foods, there are 

 large numbers of bacteria which are of a harmless nature. 

 Some are valuable and beneficial to man, particularly 

 those which assist in plant nutrition and in the prepara- 

 tion and digestion of foods. 



