ACTINOMYCETES 433 



diseased tissue or with cultures results in the production 

 of pathological lesions referable to the organism; again 

 no effect follows upon such inoculation. As seen in the 

 tissues by microscopic examination, actinomycetes may 

 appear as long, convoluted, irregularly staining, beaded, 

 branching threads, or as clumps of short, markedly beaded, 

 sometimes branched rods. At times a clump of the short 

 or longer threads is encountered in the tissues that gives the 

 distinct impression of mycelial structure. 



Some of the varieties that have been described are best 

 demonstrated in the tissues or exudates by the Gram or 

 Gram-Weigert method of staining; others are decolorized 

 by this process, and are rendered ^'isible only by the simpler 

 procedures. Some of them are to a limited extent proof 

 against the action of acid decolorizers. Though many 

 accounts of the presence of these morphological types in a 

 variety of conditions have been recorded, the descriptions 

 in the main are meagre and often insufficient for identifi- 

 cation. A few, however, have been found so constantly in 

 association with more or less definite clinical and pathological 

 conditions that a brief description of them may be of service. 



Actinomyces Bovis (also commonly known as streptothrix 

 actinomyces, actinomyces fungus, ray fungus) was first 

 observed by von Langenbeck in a case of vertebral caries 

 in 1845. According to Bollinger, the fungus had been seen 

 by Hahn a number of years before in museum specimens, 

 but had been regarded by him as a penicillium. The name 

 actinomyces or ray fungus originated with Harz. It is con- 

 stantly to be detected in the tissues and exudates of the 

 disease of cattle known as actinomycosis, "lumpy jaw," 

 "wooden tongue," etc. The typical tumor of this disease 

 is characterized by inflammation, pus formation, excessive 

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