138 BACTERIOLOGY. 



them after two or three days, we shall find no 

 change in the anthrax tube ; the bacillus being 

 eminently aerobic, no growth whatever has oc- 

 curred. In the tube containing the bacilli of 

 malignant oedema there will be a more or less 

 characteristic cultivation. 



The nitrogen which is essential for building up 

 their protoplasm can be obtained either from 

 albumins, or from ammonia and its derivatives. 

 That the albumins can be dispensed with was 

 shown by Pasteur, who employed an artificial 

 nourishing solution built upon a formula repre- 

 senting the essential food constituents (p. 91). 



Carbon is derived from such substances as cane 

 sugar, milk sugar, and glycerine, and, in some 

 cases, by the splitting up of complex proteid 

 bodies. 



Water is essential for their growth, but depriva- 

 tion of water does not kill all bacteria. Desicca- 

 tion on potato is employed for preserving some 

 micro-organisms, as a new growth can be started, 

 when required, by transferring some of the dried 

 potato to fresh nourishing ground. Comma-bacilli, 

 on the other hand, are destroyed by drying. Sugar, 

 by abstracting water, prevents the development of 

 micro-organisms in preserves. 



Mineral or inorganic substances, such as com- 

 pounds of sodium and potassium, and different 

 phosphates and sulphates, are necessary in small 

 proportions. 



