158 CHROMOPAROUS BACTERIA. 



as a result of the system of cultivation preferred by him, unwittingly 

 deprived the bacillus of its property of elaborating the green fluor- 

 escent colouring matter. 



During the past two decades there has been isolated from 

 water, air, and soil a number of blue-producing species of Schizo- 

 mycetes, which, however, are of no special importance, and can 

 therefore merely be mentioned here, though fully described in 

 Eisenberg's work. They are : Bacillus janthinus, obtained by Zopf 

 from the river Panke, Berlin ; Bacillus berolinensis i?idicus, by 

 H. CLAESSEN (I.) from the Spree; Bacillus lividus, by Plagge from 

 Berlin town- water; Bacillus casruleus, by ALLEN J. SMITH (I.) from 

 the water of the Schuylkill river. It is probable that these species 

 are chromoparous, as was established with certainty in the case of 

 a fission fungus obtained by Voges from natural water in Holstein 

 (and also named Bacillus coeruleus), which excretes the blue colour- 

 ing matter into the surrounding medium, where it collects into 

 small granules. 



At the present time a fairly large number of species producing 

 violet pigments are known ; they are found in the same places as 

 the above-named, and are equally of little practical importance. A 

 few may be cited as examples, the oldest species known being the 

 Bacteridium violaceum, observed by Schroeter, and named Micro- 

 coccus violaceus by Cohn. This organism develops on solid media 

 (gelatin, potatoes, &c.) to solid-growing violet-blue colonies. In 

 contrast to this is Bacillus violaceus, which liquefies gelatin and 

 produces a deep violet colour. Bacillus membranaceus amethystinus 

 was discovered by Jolles in Spalato well-water, and produces a dark 

 violet pigment exhibiting a metallic lustre. 



98. Green Bacteria 



were observed by Schroeter, and COHN (I.) named one such 

 species (producing a sap-green colour) Micrococcus clilorinus. VAN 

 TIEGHEM (III.) introduced into the literature of the subject two 

 new green non-motile species under the names of Bacterium viride 

 and Bacillus virens. The Bacterium chlorinum, discovered by 

 ENGELMANN (VII.), is more highly interesting. It is endowed with 

 powers of locomotion, and when present in microscopic prepara- 

 tions where there is a lack of oxygen it strives to reach such spots 

 as are illuminated by white, yellow, or red light. The three last- 

 named species are not chromoparous, but chroniophorous bacteria. 

 "W. SYMMERS (I.) described a Bacillus viridans. Reference may 

 be made in this place to a treatise on the green bacteria by 

 P. A. DANGEARD (I.). 



Green, fluorescent transformation products are excreted by 

 very many species of bacteria, a number of which are described in 

 Eisenberg's work. At present mention of three will suffice, viz., 

 the gelatin-liquefying Bacillus fluorescens liquefaciens, and the 



