CH. viii.] BACTERIUM. 89 



the zoogloea is dendritically ramified (Zoogl&a ramigera, 

 Itzigsohn), as seen on the surface of fluids containing 

 decomposing algae. 



i. Septic Bacteria. With Cohn we distinguish two kinds : 

 Bacterium termo and Bacterium lineola. 



(a) Bacterium termo. The elements are short and cylin- 

 drical, about 0-0015 mm - l n g> a tn i r d l ess * n breadth, and 

 appear generally as dumb-bells. They are common in 

 putrefying fluids, indeed they form the essential cause or 

 ferment of decomposition, being the true saprogenous 

 ferment (Cohn). They are invested in a thick membrane, 



/ * 



f 



FIG. 34. BACTERIUM TERMO FROM FIG. 35. ZOOGLCF.A OF BACTERIUM 



AN ARTIFICIAL CULTURE. TERMO. 



and are flagellate. With the end of putrefaction they 

 disappear. They grow well in Cohn's nourishing fluid, and 

 I have found them as constant inhabitants of unfiltered 

 distilled water in the laboratory ; so much so that with a 

 drop of this water I am always able to start a copious growth 

 of bacterium termo in pork broth, Agar-Agar, &c. When 

 cultivated in the incubator at 32 to 36 C. in suitable 

 nourishing material (pork broth, chicken broth,) they 

 produce a uniform turbidity, and after several days an 

 attempt at a pellicle, the whole nourishing fluid becoming 

 thicker. But after from several days to a few weeks the 

 cultures die, a fact which distinguishes them from all other 



