SPIRILLUM VOLUTANS. 483 



made from vegetable tissues (portions of potato, &c.), 

 Prazmowski was able to observe that the rods of Vibrio 

 rugula collected around the cell walls of the tissue, and 

 that they broke up in a short time (3 or 4 days) into 

 swarms of Vibrio rugula. The intimate nature of the 

 fermentative action has not as yet been ascertained. 



Spirillum serpens ( Vibrio serpens). Threads thinner, 

 3 to 4 regular and permanent bends, 11 to 28 /*. in 

 length, "8 to I'l /*. in thickness ; at times united in 

 chains. Actively motile ; often in dense masses. Occurs 

 frequently in various stagnant fluids. 



B C ' 



Fig. 133. 



A, Spirillum (vibrio) serpens. 7?, Spirillum tenue. 



C, Spirillum undula X 650. 



Spirillum tenue. Threads very thin, at least 1J turns 

 of a screw, at most, however, 2 to 5 ; the space 

 between the individual turns is from 2 to 3 /*., the 

 length of the spirilla being therefore 4 to 15 /*. ; they 

 move with lightning rapidity. It often occurs in dense 

 masses in decoctions of plants. 



Spirillum undula. Threads 1'] to 1'4 /*. in thickness, 

 8 to 12 p.. in length, turns wider, 4 to 5 /*. in height. 

 Each thread has li to 3 turns. Kapid simultaneously 

 turning and shooting movements ; a flagellum can be 

 distinctly seen at each end in the form of a long, 

 slightly arched, and powerful thread, becoming thinner 

 towards its end. It occurs in the most various kinds of 

 putrefying fluids. 



Spirillum rolutans. Threads, 1'5 to 2 /*. in thick- 

 ness, 25 to 30 p. in length, somewhat thinner and 

 rounded at the ends, with thick, dark, granular contents. 

 Each thread has 2J to 3^ turns, the interval being thus 

 from 9 to 13 p. Sometimes motile, sometimes non- 

 motile ; a distinct flagellum at each end. It occurs in 

 marsh water, and it has been foun 1 in a decoction of 

 dead fresh-water snails. 



