NOMENCLATURE AND CLASSIFICATIONS. 169 



rein thierischer Character, erkannt" (p. 74). At this time his genus was reduced to 

 one species, that with which he started out, viz, B. triloculare. 



Ganz sicher ist nur eine Art der Gattung (p. 75). 



Von den im Jahre 1828 aufgefiihrten 3 Arten ist nur B. triloculare als Stamm ver- 

 blieben, die beiden andern, B. stintillans und simplex, sind unter diesen Namen zur 

 Gattung Monas gestellt (p. 77). 



In the Vibrionides stress is laid on the incomplete self-division by which they 

 form motile jointed threads (bewegte Gliederfaden) (p. 74). Bacterium is non-flexile 

 (unbiegsam) ; Vibrio is flexile (schlangenfbnnig biegsam) (p. 75). Bacterium can 

 only swim straight ahead. There is a more decided " Einschniirung und grosseren 

 Isolirung der Einzelthiere " in Vibrio than in Bacterium. In both genera division 

 takes place at a right angle to the long axis. 



Bacterium triloculare (fig. 138) consisted of oval corpuscles developing into 

 short cylinders with rounded ends, 2 to 5 times as long as broad (usually 3 times), 

 having as many transverse rays [septa]. It was found in 1820 in swamp water in 

 the oasis of Jupiter Ammon, in Libya. In 1831, near Berlin, Ehrenberg found a 

 supposedly similar organism which he named Bacterium articulatum. Subsequently 

 he says he rediscovered this organism in standing, " modri- 

 gen " water in a glass in his room, and finding what he 

 considered to be transition forms, he abandoned the latter 

 name and united all of these organisms, whatever they may 

 have been, under the name of B. triloculare. The state- 

 ments about the flagellum, and the figures of 1838, appear to 

 have been drawn wholly from the Berlin forms, supposed to be 



identical with the African ones. The organisms were colorless and non-flexile and 

 self-division was observed. Contents very finely granular. Sluggishly motile, but 

 " zahlreich und deutlich durcheinander fahrend." The size of the African form is 

 said to be ^ linie ; the Berlin forms were ^ to ^ linie. The single " Thierchen " 

 in the Berlin form was one-fifth as long, i. e., ~ linie. Ehrenberg's figures repre- 

 sent a magnification of X 290 and X 1,000 and are much better than those of 

 B. triloculare in the earlier work. They show a transversely 2 to 5 septate, rod- 

 shaped organism, with rounded extremities, and bearing one polar flagellum about 

 one-third the length of the body. There are no paired rods, or constrictions at any 

 of the septa, but some of the rods are slightly curved. The shape and septation of the 

 figures is slightly suggestive of some of the drawings of de Bary's Bacillus megate- 

 rium (Pilze Mycet. u. Bact, fig. 194). They also look somewhat like some of the 

 involution forms of Bacillus hortulanus (Phil. Tr. Royal Soc., Series B, vol. 191, 

 pi. 1 6). Both of these organisms, however, have peritrichiate flagella. The flagel- 

 lum resembles that on species of Vibrio. 



Cohn's drawings of Bacterium termo are shown in fig. 139, copied from his 

 " Beitrage " (Bd. I, Heft 2, Tafel III). Cohn did not consider motility of any generic 

 value, and consequently paid no attention to organs of motion. Dallinger & Drys- 



*FiG. 138. Ehrenberg's Bacterium triloculare, showing flagella. From Die Infusionsthierchen, 

 Plate V. fig. I. i, 2. 



