x.] BACILLUS. 79 



out by continuous divisions into a long chain of bacilli, thus 

 forming, as it were, a side-branch. Some of the threads are 

 wavy and curved ; most of them are, however, straight Zopf l 



FIG. 43. -STREPTOTHRIX FOERSIERI FIG. 44.-CLADOTHRIX DICHOTOMA 



(AFTER COHN). (AFTER COHN). 



claims to have observed that the threads of the cladothrix 

 gave rise to micrococcus, bacterium, bacillus, and spirillum ; 

 and states that each of these is again capable of growing into 

 the threads of the cladothrix. But these observations were not 

 made after exact methods. 



(e) Beggiatoa.ln stagnant water, particularly in sulphur- 

 containing water, peculiar oscillating colourless threads are 

 met with of the thickness of O'OOl to 0'016 mm. ; they contain 

 highly refractive granules, which Cohn (Beitrage zur Biol. d. 

 Pfl. I. 3) has shown to be composed of sulphur. After dis- 

 solving these granules it is seen that each thread is septate, 

 being composed of a sheath and transverse septa at regular 

 intervals, by which the threads appear made up of a series ^of 

 short cylindrical elements. There are a number of species 

 varying from one another in the thickness of the threads. 



1 Zur Morpholooie der Spaltpflanzen, Leipzig, 1862 : see also Cienkowski. 



