576 APPLICATION OF METHODS OF BACTERIOLOGY 



of which there appear to be several, evade all efforts to 

 isolate them from the soils and to cultivate them by the 

 methods commonly employed in bacteriological work. 

 They can be successfully studied only through the employ- 

 ment of special media. 



The organism generally known as the nitro-monas of 

 Winogradsky is a short, oval, and frequently almost spherical 

 cell. It reproduces by segmentation as usual for bacteria, 

 but there is little tendency for the daughter-cells to adhere 

 together or to form chains. In cultures they are commonly 

 massed together, by a gelatinous material, in the form of 

 zooglea. It does not form spores, and is probably not 

 motile, though Winogradsky believes he has occasionally 

 detected it in active motion. As has been stated, it does not 

 grow upon ordinary nutrient media, and cannot, therefore, 

 be isolated by the means commonly employed to separate 

 different species of bacteria. The most astonishing property 

 of this organism is its ability to grow and perform its specific 

 fermentative function in solutions devoid of organic matter. 

 It is believed to be able to obtain its necessary carbon from 

 carbon dioxide. For its isolation and cultivation Wino- 

 gradsky recommends the following solution: 



Ammonium sulphate . 1 gram 



Potassium phosphate 1 gram 



Pure water . . . . 1000 c.c. 



To each flask containing 100 c.c. of this fluid is added from 

 0.5 to 1 gram of basic magnesium carbonate suspended in 

 a little distilled water and sterilized by boiling. One of the 

 flasks is then to be inoculated with a minute portion of the 

 soil under investigation, and after four or five days a small 

 portion is to be withdrawn, by means of a capillary pipette. 



