PATHOGENIC STREPTOTHRICES. 361 



duction of pathological lesions referable to the organism ; 

 again, no effect follows upon such inoculation. As seen 

 in the tissues by mici-oscopic examination, streptothrices 

 may appear as living, convoluted, irregularly staining, 

 beaded, branching thi-eads, 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-^Yeigert method of staining; others are 

 decolorized by this process, and are rendered visible 

 only by the simpler procedures. Some of them are to 

 a limited extent proof against the action of acid decolor- 

 izers. 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 identification. A few, how- 

 ever, have been found so cc>nstantly in association with 

 more or less definite clinical and pathological conditions 

 that a brief description of them may be of service. 



Stbeptotheix ACTINOMYCES (also commonly known 

 as actinomyces bovis, 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 constantly 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 



