192 SULPHUR BACTERIA 



division, and that such fragmentation is associated with cell 

 division, his view would be considerably strengthened. This 

 organism, however, is far from being a typical sulpliur microbe, 

 and in all probability should find a place among the Flagellates. 

 It is noteworthy that even in such large cells as Beggiatoa 

 mirabilis, in which, if present, the typical nucleus would be 

 a prominent object, there is no trace of it. 



The cytoplasm does not call for special mention, except to 

 stress the fact that in no single instance is there a differentiation 

 between a peripheral and a central cytoplasm based on a marked 

 difference in the size of the vacuolar meshes. 



Cell Inclusions. — Sulphur appears to be the inclusion which 

 is common to all these organisms. As they flourish under 

 marine, brackish, and fresh water conditions, it is probable 

 that the total number of metabolic products is very large, 

 and that the different organisms show considerable variety in 

 this respect. The chemical analysis of the sulphur bacteria 

 on a large scale has yet to be made. 



Interesting inclusions are the lime granules of Chromaiium 

 Lmshaiieri. In this organism also are small round bodies 

 which may be stained with methylene blue, and which are 

 probably protein reserve products. The minute granules 

 that are found in Beggiatoa mirabilis, Beggiatoa alba, and 

 Thiovulum majiis, are probably of the same nature. 



The core to the sulphur granules which was found in 

 Thioporphyra volutans appears to be the same as the " sulphur 

 builders " which Hinze found in Thiophysa volutans. It is 

 probable that in all sulphur bacteria the sulphur globule has an 

 organic core, and that it plays an important role in the meta- 

 bolism of the sulphur bacteria. 



The apparent secretion of the sulphur globule into a vacuole 

 recalls the mode of formation of the spore in the genus Bacillus ; 

 see A. Meyer, and Ellis (i), and the formation of the spore in 

 the genus Sarcina (Ellis (i)). 



