The Minute Structure of the Vinegar Plant. 239 



does not seem an essential characteristic, and we shall only 

 follow good authorities if we admit quiescent objects, which have 

 the same form and exercise analogous functions, as members of 

 the same family. 



The usual divisions of vibrions into genera and species, we 

 apprehend, satisfy nobody. Some are larger, some shorter, 

 some divide obliquely, some at right angles to the longer axis. 

 Some are like miniature corkscrews, and so far resemble that 

 pretty confervoid plant the Spirulina. These latter move spi- 

 rally, and often with rapidity. Others twist and wriggle, others 

 oscillate, and others stand still. 



The Micrograpliic Dictionary provisionally places some 

 vibrions among the confervoid Algae, and probably all will be 

 distributed between the Algse and the Fungi, the latter seeming 

 most likely, to the writer, to carry off the greatest number. 



In Pritchard's Infusoria, p. 531, the genus Bacterium, of 

 Dujardin, is described as characterised by straight slightly 

 flexible threads more or less distinctly jointed, and slow in their 

 movements. In the next page all the species are said to have an 

 active power of locomotion. The activity of motion certainly does 

 not afford ground for generic or specific distribution, and some 

 that are active at one time appear to be quiescent at another. 

 For convenience, Dujardnr's division may be adopted, as 

 founded upon external characteristics easily distinguishable in 

 extreme cases, though liable to be more or less confounded in 

 intermediate forms. According to this, first comes Bacterium, 

 the description of which we have just cited. Then we have 

 " Vibrio, either straight or nexuose, with a more or less viva- 

 cious writhing movement;" and then "Spirillum, having the 

 form of a corkscrew, revolving on their long axes, oftentimes 

 with great rapidity, but never straight." They are all small 

 bodies ; few exhibit the beaded structure with less than an 

 amplification of 500 diameters, and some defy a power of 2000 

 linear, which leaves them extremely minute in length, as well 

 as in breadth. Ehrenberg constituted six genera of vibrions ; 

 and Pasteur, speaking of them, says that they can all exist 

 without free oxygen, and perish in contact with it, if nothing 

 preserves them from its action.* To Monas crejmsculum and 

 Bacterium termo he ascribes the disappearance of oxygen from 

 putrefying infusions, and then he tells us the vibrions appear 

 and do their work as ferments, pulling to pieces the complicated 

 organic atoms in a definite way. If this view should be con- 

 firmed, it may serve as the foundation for a natural division of 

 the vibrion family : those which live in oxygen and perform one 

 set of functions being distinguishable by action and habit, if 

 not always by appearance, from those which perish in oxygen 

 * See Intellectual Obsebveb, Sept., 1863, p. 101. 



