56 



THE ACTINOMYCETES, Vol. I 



1875) . Some of the more significant systems, 

 in which the actinomycetes were given im- 

 portant consideration, may he summarized 

 here. 



Earlier Systems of Classijication 



Migula (1894) placed the actinomycetes 

 (Strcptothrix Cohn emend) under the Chla- 

 mi/dohacteriaceae. Lehmann and Neumann 

 (1896) included the actinomycetes among 

 the bacteria-like Hyphomycetes, \vhich were 

 separated from the true bacteria. They con- 

 sidered three genera at first : Corynebacterium 

 Lehmann and Neumann, Mycobacterium 

 Lehmann and Neumann, and Oospora Wall- 

 roth. The last comprised the forms which 

 gave "Mycelium filaments long, often bent, 

 without sheath, with true branching. Many 

 species produce conidia on aerial hyphae. 

 Not acid-fast." Chester (1897) created a new 

 order, M ycobacteriaceae in which he included 

 Corynebacterium, and Mycobacterium., and, 

 like Migula, placed the actinomycetes under 

 the name Streptothrix among the Chlamydo- 

 bacteriaceae. 



In 1899, Chester revised his classification 

 and included Streptothrix among the Myco- 

 bacteriaceae. The genus was described as 

 follows: "Cells in their ordinary form as long 

 branched filaments. Produce conidia-like 

 bodies. Cultures generally have a mouldy 

 appearance due to the development of aerial 

 hyphae." 



Schahad (1904) divided the actinomycetes 

 into two groups: Actinomyces typica, with 

 thickened mycelium, and Actinomyces aty- 

 pica, with nonthickened mycelium. 



Jordan, in 1908, divided the thread-form- 

 ing bacteria into four genera under Tri(^ho- 

 mycetes : 



1. Filaments unbranched — Leptothrix 



2. Filaments with pseudomembranes — 

 Cladothrix 



3. Filaments with true branches: 



a. Reproductive elements, spores ob- 

 served — Nocardia 



b. No spores observed — Actinomyces 



H. W. Conn, in his Agricultural Bacteriol- 

 ogy (1909), divided the higher bacteria into 

 four genera: Cladothrix, Leptothrix, Strepto- 

 thrix, and Actinomyces. Orla-Jensen (1909) 

 created a family ^ — Actinomycetes in the order 

 Cephalotrichinae. This family was divided 

 into four genera: Rhizomonas (nodule-form- 

 ing bacteria), Corynemonas (parasites, non- 

 acid-fast), M ycomonas (parasites, acid-fast), 

 Actinomyces (much branching mycelium). 



Engler (1912) placed the actinomycetes 

 among the Eubacteria, in the family Actino- 

 mycetaceae, under one genus Actinomyces: 

 "Filamentous colonies with true branching; 

 radiating, nonmotile. Filaments dividing into 

 oidia." 



Chalmers and Christ opherson (1916) 

 proposed a system of classification based 

 upon the pigmentation of the granules in the 

 infected material. 



1. Actinomycotic granules black, not 

 cultivated on artificial media. 



2. Granules yellow, orange, red, or color- 

 less, divided into two species: 



a. Cohnistreptothrix — anaerobes, culti- 

 vated with difficulty. 



b. Nocardia — aerobes, cultivated read- 



ily. 



Krainsky divided the actinomycetes, on 

 the basis of colony size, into Macroactino- 

 myces and Microactinomyces. 



Buchanan (1917, 1918) created a new 

 order Actinomycetales, which included a 

 single family, Actinomycetaceae. This family 

 was di^'ided into four genera, two of which — 

 Actinomyces and Nocardia — are most perti- 

 nent to this treatment. This system, because 

 of its historical significance is given here in 

 detail. 



Actinomycetales 



Syn. Actino))ii/ct'lcs lialbiaiii, T lichobacteriaceae 

 Fischer 



Mold-like organisms, not typically water forms, 

 saprophytic or parasitic. Sheath not impregnated 

 with iron, true hyphae with branching often evi- 

 dent, conidia may he developed, but never endo- 



