OF THE VIBRIONIA. 531 



(E.) or Bacterium Termo(D\\}.)w,, according to his Avell- conducted investiga- 

 tions, no other than the swarming stage of a microscopic aquatic fungus 

 belonging to the Mycophyceae, of which he makes a new genus, named 

 Zoogloea : again, Sjnrochceta jylicatilis is, in his opinion, an Alga of the genus 

 Sinrulma, and the stiif Vibrios allies at least of the Oscillaria)a, of the genus 

 Beggiatoa ; the shorter Vibrios and Sjpirilla likewise resemble Oscillarisea and 

 Spirulina. 



Should Cohn's opinions be confirmed, the Vibrionia, as a distinct family, 

 would be well nigh broken up. In fact, his views are generally acceded to ; 

 for Perty, Bm^nett, and others all point out their peculiar affinities with the 

 Oscillariae, and discover similar forms among the transitional phases of various 

 Algae, and, indeed, among the antheridial spores of higher plants. The 

 value of Spirodiscus as a genus is little insisted upon by Ehrenberg, who 

 instituted it ; and in all probability it should be set aside, and Spirochceta also 

 be sacrificed with it. The only species of Spirodiscus named, Perty surmises, 

 might have been nothing more than the spore of a fungus. Dr. Burnett has 

 expressed himself as follows to the same effect ; for he observes, " When we 

 come to organisms as minute as these, the distinguishing characteristics of 

 genera and species become too obscure and equivocal to have much value ; and 

 the best microscopists have arrived at the conclusion that such distinctions 

 are too refined and will not bear the test of exi^erience. 



" The genus Vibrio — the simplest — I regard as the first appearance of the 

 young Alga, existing then as the smallest cells, arranged in linear series. 

 The genera SpiriUum and Bacterium, composed of larger forms, and of a finer 

 and more solid structure, represent the more advanced forms ; and as all Algoe, 

 as they advance in size, tend to consolidate into mycodcrmous forms, losing 

 much of their primitive cell-structure, so these two genera appear to have lost 

 their old beaded type. As for the two remaining genera, Spirochwta and 

 Spirodiscus, but little is positively known. They scarcely appear to belong 

 to the other forms of this family ; and as Ehrenberg himself has expressed a 

 doubt upon the subject, one may as well omit a fiu-ther notice. Therefore, 

 in a stmctural point of view, the species of this family seem to be only Algoe 

 at different stages of growth." 



Dujardin instituted only three genera of Vibrionia, viz. : 1. Bacterium — 

 straight, slightly flexible threads, more or less distinctly jointed, and slow in 

 their movements ; 2. Vibrio — either straight or flexuose, with a more or less 

 \'ivacious writhing movement ; 3. Sp)irillu7n — having the form of a corkscrew, 

 revolving on their long axis, oftentimes with great rapidity, but never straight. 

 Perty has made a more ambitious attempt to classify these minute organisms ; 

 of its utility, however, little can be said, for oiu' acquaintance with them is too 

 imperfect to establish satisfactorily any .distribution of them. To resume: 

 Perty makes a section of his heterogeneous group Phytozoida, which he calls 

 Lampozoidia, represented by the one family " Vibrionida." The *^ Lampo- 

 zoidia " are defined as " colourless, or rarely blue, yellow, or red, never green, 

 organisms, without special organs, and with scarcely a trace of differentiation 

 of substance. Their motions, though seemingly voluntary, are in fact only 

 automatic. They multiply by transverse fission, and in so doing produce chains 

 and fibres." Of the family Vibrionida, two varieties are distinguishable : — 

 A. Spirillina, in which the chain or fibre is spii^ally coiled ; B. Bacterina, in 

 which it is contorted or straight. Spirillina contains two genera, Spirochceta 

 and Spirillum ; whilst Bacterina is made up of four, viz. Vibrio, Bacterium, 

 Metallacter, and Sporonema. The new genera named will follow after our 

 account of those recognized by Ehrenberg, and the notes on the others in 

 their proper places. 



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