458 APPLICATION OF METHODS OF BACTERIOLOGY 



ited by bacterial spores, and are stainable by the ordinary 

 methods. 



The limits of this group are ill defined and its recognized 

 components are not as a whole well understood. 



The longest known and most carefully studied actinomy- 

 cetes are act. bovis, act. madurce, act. farcinicus, and act. 

 Eppingeri, although many other varieties have been en- 

 countered in association with important and interesting 

 pathological lesions. 



The fact that certain bacteria, viz., B. tuberculosis, B. 

 mallei, B. diphtherise are, as a rule, segmented and occa- 

 sionally show a tendency to branch, has led to their being 

 classified at times with the actinomycetes. On this point, 

 however, there is as yet no concensus of opinion. 



It is interesting to note that the pathological lesions in 

 which actinomycetes have been detected show in many cases 

 certain similarities to true tubercular processes, and in few 

 instances, save for the absence of tubercle bacteria, as we 

 usually see them, were indistinguishable from tuberculosis. 



More or less imperfectly studied varieties of actino- 

 mycetes have been encountered in abscess of the brain, 

 cerebrospinal meningitis, endocarditis, bronchopneumonia, 

 pleuropneumonia, pustular exanthemata, abscess of the lung, 

 bronchiectasis, pulmonary gangrene, necrosis of the vertebrae, 

 subphrenic abscess, noma, and pseudotuberculosis. 



In some cases the actinomycetes can be obtained in culture 

 from the diseased tissues; almost as often they can not. 

 Sometimes the inoculation of animals with bits of the 

 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 



