MICROORGANISMS AND FERMENTATIONS 7 



it retains its sharp contour, it is known as a capsule. Numbers 

 of cells may thus form large jelly-like masses, known as zoogloea 

 Occasionally the cell walls will become assimilated with the 

 surrounding liquid, which then becomes slimy or ropy throughout 

 (see Figs. 13, 14 and 15). 



FIG. 12. Zoogloea of " Leuronostoc," a Coccus which forms slimy lumps in Cane 

 Sugar Solutions. (After Zopt.) x 1,200. 



FIG. 13. The Bacterium of " Long Milk." Capsule Stage. 



X 1,000. 



Milk not yet slimy. 



NUTRITION 



The following twelve elements enter into the composition of all 

 organisms : Oxygen, Hydrogen, Carbon, Nitrogen, Sulphur, 

 Phosphorus, Chlorine, Sodium, Potassium, Calcium, Magnesium 

 and Iron. It follows that substances composed of these elements 

 are necessary for the normal growth of microorganisms. Some of 

 them, e.g., sulphur, calcium and iron, are only used in such minute 



