1878.] 



On the Life-History of Spirillum. 



481 



IX. " On the Life-History of Spirillum." By Patrick Geddes 

 and J. COSSAR Ewart, M.D. Edin., University College, 

 London. Communicated by Professor Huxley, Sec. R.S. 

 Received June 20, 1878. 



[Plates 11, 12.] 



Notwithstanding the numerous and fruitful researches which have 

 been recently made into the life-history of Bacteria, our knowledge of 

 the common and interesting curved and spiral forms— the Vibrio* and 

 Spirillum of Ehrenberg — has made little or no advance since his time, 

 neither embryonic nor reproductive forms having ever been observed ; 

 while even the zooglcea phase, so characteristic of Bacterium and 

 Bacillus, has only once been mentioned,f and then in a different form. 



A fresh- water aquarium, which has been stagnating since last 

 summer in the Physiological Laboratory of University College, con- 

 tained in winter vast numbers of ordinary motile Spirillum. On 

 recently re-examining the water, one zooglcea film after another having 

 in the meantime formed on the surface, thickened, broken, and sunk, 

 we found that these motile forms had almost disappeared, while the 

 films consisted almost entirely of resting Spirillum in a gelatinous- 

 looking matrix, similar to that of Bacterium and Bacillus. Among 

 these were two or three apparently distinct kinds of filaments, some 

 resting and colourless, others motile, and filled with highly refracting 

 bright yellowish-brown spheres. Such a field is represented in fig. 1. 



The glcea had, even to the naked eye, a brownish tint, which under 

 the microscope was distinctly traceable to the Spirilla, the matrix 

 being also faintly tinged. When a fragment was mounted, water 

 very rapidly revived the perfectly quiescent organisms at the torn 

 edges. These, after some efforts, succeeded in disengaging them- 

 selves, and in a few seconds were darting to and fro, fully motile. 

 The rapidity and extent of this change from the resting to the motile 

 condition, which we have witnessed again and again, was of extra- 

 ordinary interest and beauty. When crowded into a narrow space, 

 the motile Spirilla showed their bright brown madder tint very 

 intensely — a single one, unless very carefully examined, appearing 

 colourless (fig. 1). 



The resting Spirilla are of very various shapes, some singly bent, 

 others slightly curved at one or both ends, and others coiled like 

 corkscrews of two or more turns (fig. 1). We were much astonished 



* We are very strongly of the opinion that the forms described by various 

 authors as Vibrio are merely either — (1.) Zigzag dividing Bacillus; (2.) Slightly 

 waved Bacillus ; or (3.) Undeveloped Spirillum, and hence that Vibrio shoidd no 

 longer be used as a generic term, 



f Lankester, " Quart. Journ. Micr. Sci.," vol. xiii, p. 4-24. 



