GENERAL SYSTEMATIC BACTERIOLOGY 263 



that group of the family Chlamydohacteriaceae in which the cells are 

 more or less branched. Mace (1897, p. 1024) came to the conclusion 

 that the Cladothrix dichotoma of Cohn did not exist as a well defined 

 type, and that it had been interpreted in different ways by various 

 investigators. He therefore proposed that Cladothrix be substituted 

 for Streptothrix Cohn, because the latter generic name is a homonym 

 of Streptothrix Corda. His definition reads: 



Ces sont des Bact^ries filamenteuses, a 61^ments droits ou sinueux d^pourvus 

 de gaine, produisant lat^ralement des ramifications disposess d'une facon irregu- 

 liere ; dans certaines conditions, les filaments se segmentent ou tres courts baton- 

 nets ou articles sph^riques ou ovoides que I'ou doit probablement consid^rer 

 comme arthrospores. 



The conclusions of Mace have not been generally accepted, and his 

 statements have but served to confuse nomenclature. 



Kligler (1915, p. 327) described a Cladothrix placoides from the teeth. 

 Some fifty-eight strains were studied. The characters are given as 

 follows : 



Morphology. The morphology of this organism is very variable. It often 

 appears like a coccus, sometimes like a diphtheroid rod, or short club-end thread. 

 Usually one finds all three in the same preparation. The coccus-like forms are 

 probably spores, and the others are pleomorphisms of the thread. Microscopic 

 pictures are often obtained which look identical with L. innominata of Miller. 



Chromology. It stains readily with ordinary anilin dyes and is usually Gram- 

 positive. Often the spore retain the stain while the threads are decolorized when 

 treated by Gram's method. Biological properties. They are aerobic, non-motile, 

 non-branching threads. They grow best at 37°C., only very slowly at 20°C. 



Cultural characters. On agar they form round, raised, lustrous, white colonies 

 which can be picked up entire from the medium. On glucose-agar the colonies 

 are usually larger and more grayish. Microscopically the surface colonies are 

 convoluted and are often seen on the plates enclosing underneath them small 

 colonies of other bacteria. In broth the growth is very sparse, and the wall of 

 the tube is usually covered with a granular layer of discrete colonies 0.5 mm. or 

 less in diameter which are not readily removed by shaking the tube. In glucose- 

 broth the growth is very abundant, giving both a heavy turbidity and a granular 

 deposit on the wall. Gelatin was liquefied by some strains but not by others. 

 They all fermented glucose, most of them fermented sucrose, while some also 

 fermented lactose. Gas is not produced. They generally reduce nitrates and 

 fail to produce indol or ammonia. When first isolated they should be kept on 

 glucose-agar and transferred every two weeks. 



Buchanan (1918, p. 302) rejected the name as invalid as a bacterial 

 genus because of its use for a phanerogam. 



