An investigation into the life-history of cladothrix dichotoma (Cohn)

The nameCladothrix dichotoma was first applied to this organism by Cohn in 1873. In 1875 he also founded the genusStreptothrix to include an organism (S. Foersteri ) which differed fromCladothrix mainly in the possession of a mycelial habit. In 1887 the genusActinomyces was also instituted by the same writer, to include the newly discoveredA. bovis . Whatever may be the value of the distinction made by Cohn betweenStreptothrix andActinomyces , there is no doubt whatever about the clearness of the line of separation which he set up between these genera andCladothrix . Unfortunately, later writers have used the termCladothrix to indicate not only the only organism belonging to the group, but also species belonging toStreptothrix . As examples may be mentioned the organism described by Cienkowski (3) in 1877, which he describes as having a branched mycelial habit. The same mistake was made by W inter (21) in 1884. Influenced, doubtless, by these descriptions, Macé (14) in 1884 denied the separate identity ofStreptothrix andCladothrix . In his work he describes the characteristics ofStreptothrix , and gives, under this name, precisely those defined by Cohn as belonging to the genusStreptothrix . The confusion by this time had become fixed, and we find the same mistake in later writers. Thus Günther and Rullmann (10), in 1896, describe asCladothrix odorifera what is obviously aStreptothrix . Again, Acosta and y Grande Rossi (1) describe asCladothrix invulnerabilis an organism with a branched mycelium and “ aërial hyphal threads.” The same indubitable characteristics ofStreptothrix are to be found in Eppinger’s (5)Cladothrix asterioides , and in Hesse’s (2) and Garten’s (9)Cladothrix liquefaciens , likewise in the organism described asCladothrix by B. Fischer (7), Kedzior (13), Naunym (16), Tchierchke (19), and Flügge (8). Some investigators had avoided this mistake. The first, since Cohn, was Zopf (22), whose masterly treatise, despite small errors in detail, contains the best morphological account ofCladothrix dichotoma which has yet been published. We are also indebted to Büsgen (2) and to Hoeflich (12) for several valuable additions to our knowledge of this organism, and particularly because their observations were taken from pure artificial cultures. To Büsgen belongs the credit of being the first to obtain a pure culture of this species, while the fullness of Hoeflich’s account of growth in artificial media leaves nothing to be desired. On the other hand, the researches of Sauvageau and Radais (18) have put our knowledge of the genusStreptothrix on a firm basis. We know now that the two groups are, phylogenetically, very far apart, and that, with one exception,Cladothrix dichotoma stands alone in the group Cladothricaceæ. This exception isCladothrix natans ; the inclusion of this organism andCladothrix dichotoma into a single group (called Sphærotilus) by Migula (15) is a step the wisdom of which is very questionable.Distribution .—Cladothrix dichotoma was described by Zopf as the “Wasserpilz par excellence,” on account of its very wide distribution. He referred more particularly to the neighbourhood of Berlin. In the neighbourhood of Glasgow the organism does not thrive particularly well. In waters with a high organic content the predominant place is held by one or more species of the lower bacteria, or one of the higher fungi. In two places only was a predominant growth ofCladothrix dichotoma found in waters containing organic matter in solution. From one of these, a ferruginous stream running close to Possil Marsh, near Glasgow, the whole of the present observations were taken. The water which forms this stream is collected from a neighbouring cemetery that is situated on a slight eminence. This accounts for the comparatively high amount of organic matter in solution in this water.