8 4 



HARDWICRE'S SCIENCE-GOSSIP. 



53. 6". Obermeieri, Cohn. 



Morphologically almost the same as S. plicatilis, 

 perhaps only distinguished by the fact that the 

 threads are pointed at both ends. 



In the blood of persons suffering from febris 

 rccurrens, and probably the cause of the disease. 



The threads of i". Obermeieri 'are either extended in a straight 

 line, and wound in regular spirals, or else they bend themselves, 

 moving with extreme rapidity in the most varied fashion, so 

 that the spirals appear of unequal size, especially at the most 

 strongly bent places. This species is found in the blood of 

 those suffering from intermittent fever, and in fact only during 

 the recurring fever periods, or for a short time thereafter. In 

 the intervals of freedom from fever they disappear.* 



54. S. Cohnii, Winter. 



Very similar to both the foregoing species, but 

 always shorter, and for the most part more slender, 



articulations are not visible, but at times the threads 

 break up into joints. 

 In sea-water. 



The longest specimens showed sixteen turns ; 

 not been discovered. 



fiagella have 



XII. Spiromonas, Perty. Threads "flattened 

 like a leaf, twisted round an imaginary longitudinal 

 axis." Multiplication by transverse division. 



56. S. volnbilis, Perty. "Colourless, translucent, 

 smooth, without any obvious differentiation, motion 

 pretty swift, combined with a quick revolution round ' 

 the axis about which the leaf-like body is twisted. 

 Body often twisted very little, never forming more 

 than a circumference. Length 753-155"'= 15-18 /j." 



In stagnant bog-water and putrefying infusions.* 



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Fig. 62. — a and b, Spirochata plicaiilit ; c and d, S. Obermeieri {a and c after 

 photographs by Koch ; b, after Cohn ; d, after Weigert). In d the blood corpuscles 

 are represented ; the bent threads show the form assumed shortly before the 

 cessation of the fever. 



Fig. 63. — Spiromonas 

 Cohnii (after Warm- 

 ing). 



°%^ 



f* 



Fig. 64. — a, Spirillum rugula; b, S. undula; c, S. volutans 

 (a and c, after Cohn ; b, after Koch's photographs). 



than S. Obermeieri, and besides, like that, pointed at 

 both ends. 



In the slime of the teeth ; discovered by Cohn ; 

 figured by Koch, (Beitr. zur Biol., vol. ii. pt, 3, 

 pL xiv., fig. 8). 



55. S. gigantea, Warming. 



Threads cylindrical, blunt at both ends, about 3 n 

 thick, with numerous spiral turns, the height of 

 which is 25 fj., the diameter 7-9 \x. Flexile. The 



• It is a question whether this be not the same as the pre- 

 ceding species, merely transplanted into a different habitat. — 

 Tr. 



57- S. Cohnii, Warming. 



Cells flattened, but sometimes faintly angular, 

 acutely pointed at both ends, each with one flagellum, 

 with 1 \ (seldom more) turns. Spiral elongated, 6-9 

 times as high as its diameter, 9-20 /j. in height, 

 I *2-3 - 5 p. in diameter. Breadth of the cells 1*2-4 A*- 

 Colourless, often with one or two longitudinal stria- 

 tions. 



In stinking, very much decomposed water. 



XIII. Spirillum, Ehrenberg. ( Vibrio, Cohn ; 

 Ophidomonas, Ehbg.) Cells cylindrical or slightly 

 compressed, simply arcuate or spirally twisted, rigid, 

 with a flagellum at each end (? whether in all 

 species). Multiplication by transverse division, the 

 daughter-cells for the most part soon separating. At 

 times also a zooglcea is formed ; spore-formation 

 similar to that of Bacillus. 



1 unite with the genus Spirillum, the Vibrio of Cohn, and the 

 Ophidomonas of Ehrenberg. The genus Vibrio in fact cannot 

 be sharply defined, since fiagella have also been found in it. 

 Cohn himself has already united Ophidomonas with Spirillum. 

 Warming also combines all three genera. Although the name 

 Vibrio has priority, still I have preferred the designation. 



• This is often considered as an Iniusorian. See Saville Kent' s 

 " Manual," p. 244.— Tr. 



