58 



SULPHUR BACTERIA 



Jegunow (i — 5) cultivated sulphur bacteria in a flat glass 

 vessel about the length and width of an ordinary glass slide, 

 and of a depth about a sixth of the width. Some slimy m.ud 

 from the bed of one of the limans near Odessa was placed in 

 the vessel, together with water from the same source. The 

 vessel was exposed to air in an upright position. As oxygen 

 was supplied from above, and hydrogen sulphide from below, 

 : the organisms took up some intermediate position, where 

 they could obtain access to both. At the selected level they 

 formed what Jegunow names a Bacterial Plate, the shape of 



Fig. 4. 



which is shown in Fig. 4 (I) at a and on a larger scale at Fig. 

 4 (II). By altering the content of hydrogen sulphide he was 

 able at will to raise or lower the level of the bacterial plate. 

 The chief peculiarity of this plate is the series of downward 

 directed projections which are formed by it. The movement 

 of the bacteria composing each projection resembles that of 

 water in a spring. They travel down the projection, and on 

 reaching the bottom turn round and travel up again until 

 the top of the plate is reached. When viewed through a low- 

 powered microscope, when the bacteria are viewed in the mass, 

 the general appearance of a fountain is presented, which made 



