ACTINOMYCETES. 365 



tion may become segmented into short bacillus- or 

 coccus-like fragments. Furthermore, they are unlike 

 the moulds in that they have not a double wall ; are not 

 filled with fluid containing granules, and the segments 

 are not separated from one another by a distinct parti- 

 tion. They simulate the moulds in that they develop 

 from spores into dichotomously branching threads, 

 which ultimately form colonies having more or less 

 resemblance to true mycelia. Certain of the threads 

 composing such a mycelium become fruit hyphse, break- 

 ing up into round, glistening, spore-like bodies. As a 

 rule, these spores are devoid of the high resistance to 

 heat exhibited by bacterial spores, and are stainable by 

 the ordinary methods. 



The limits of this group are ill defined and its recog- 

 nized components are not as a whole well understood. 



The longest known and most carefully studied acti- 

 nomycetes are act. bovis, act. madurae, act. farcinicus, 

 ard act. Eppingeri, although many other varieties have 

 been encountered in association with important and 

 interesting pathological lesions. 



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

 mallei, b. diphtherise, generally regarded as bacteria, 

 are, as a rule, segmented and occasionally show a ten- 

 dency to branch, has led to their being classified at 

 times with the actinomycetes ; on this point, however, 

 there is as yet no consensus 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 a few instances, save for the absence of tubercle 

 bacteria, as we usually see them, were indistinguishable 

 from tuberculosis. 



