Waksman — 176 — Actinomycetes 



described a filamentous organism found in the pus of a cerebral abscess 

 as Cladothrix aster o'ldes; this organism was transferred to the genus 

 Nocardia by Blanchard in 1896 (39). In 1902, MacCallum (274) 

 reported that N. asteroides produces a diffuse peritonitis in experimental 

 animals. The characteristic ray fungus granules, consisting of elon- 

 gated cylindrical structures with laterally radiating clubs, were found 

 throughout the animal body. Generally, however, granules are not 

 considered to be characteristic of N. asteroides infection. 



It may be of interest to note here that Benbow, Smith and Grim- 

 son (30) reported that about 90 per cent of all clinical cases of acti- 

 nomycosis are caused by A. hovis. The remaining 10 per cent are 

 caused by Nocardia, some of which are acid-fast or partially acid-fast. 



Wright, in 1904, made a detailed study of actinomycosis in man and 

 in animals and of the causative agents involved. He suggested that 

 the designation "actinomycosis" be restricted to a suppurative process 

 combined with granulation tissue formation, the pus of which contains 

 the characteristic granules. These are composed of dense aggregates of 

 branched filamentous microorganisms and of their transformation or 

 degeneration products. The latter include the characteristic club- 

 shaped bodies radially disposed at the periphery of the granule. 

 Wright emphasized that cultures isolated from human and bovine 

 cases show no difference which M'ould be sufficient to justify their classi- 

 fication as separate species. He did not accept the prevalent belief, 

 based on the work of Bostroem, Gasperini, and others, that the spe- 

 cific infecting agent of actinomycosis is to be found among certain 

 branching microorganisms, which differ profoundly from A. hovis in 

 having spore-like reproductive elements. He suggested that these 

 be grouped together as a separate genus under the name Nocardia, and 

 that those cases of undoubted infection caused by them should be des- 

 ignated as "nocardioses" and not as "actinomycoses." 



Wright believed that A. hovis is a normal inhabitant of the secre- 

 tions of the mouth cavity and of the gastrointestinal tract, both of man 

 and of animals. In these secretions, it exists not in the characteristic 

 forms seen in the lesions, but as fragmented filaments growing in com- 

 pany with bacteria. He also suggested that foreign bodies so frequently 

 found in actinomycotic lesions are not carriers of the organism into the 

 tissues from without, but that their traumatic and irritative effects 

 furnish a point in the tissues for the Actinomyces to enter with the se- 

 cretions from the mouth cavity and from the gastrointestinal tract. 

 Here the organism develops into characteristic colonies and produces 

 actinomycotic lesions. 



Recent Studies:— A very extensive literature has now accumulated 

 on the etiolog)' of infections caused by actinomycetes. These are 

 usually grouped under the anaerobic and aerobic types, as brought out 



