CHAPTEE XXXIII. 



REPRESENTATIVE PATHOGENIC MICRO-ORGANISMS BELONGING 

 TO THE HIGHER BACTERIA. 



THE members of the higher bacteria which are pathogenic to man 

 have as yet been incompletely studied and classified. The following 

 divisions serve as an attempt at differentiation: 



1. Actinomyces is characterized by the radiating wreath-like forms 

 which it alone produces in the living body. 



2. Streptothrix, by its abundant true branching, wavy growth, later 

 fragmentation, and formation of conidiae, which serve as organs of 

 propagation, and in this sense may be considered as spores. 



3. Cladothrix, by its false branching, rapid fragmentation, and then 

 bacillary characteristics in old cultures. 



4. Leptotkrix, by its lack of observed branching, non-wavy growth, 

 but, on the contrary, stiff, almost straight threads, in which division 

 processes are seldom or never observed. 



These higher bacteria may rightly be considered, according to their 

 development, as a transition group between the simple bacteria and 

 the more highly developed fungi. 



The streptothrix group of micro-organisms while having many 

 affinities with the bacteria, yet differs from them in many important 

 respects which link them with the fungi. They develop from spore- 

 like bodies into cylindrical dichotomously branching threads, which 

 grow into colonies, the appearance of which suggests a mass of radi- 

 ating filaments. Under favorable conditions certain of the threads 

 become fruit hyphse, and these break up into chains of round, spore- 

 like bodies, which do not, however, have the same staining reac- 

 tions nor resisting powers as true spores. The tubercle grass and 

 diphtheria bacilli are by some believed to properly belong in the strep- 

 tothrix group, on account of the true branching forms developed by 

 them under certain conditions. The actinomyces fungus is by some 

 classed in the streptothrix group. 



The Micro-organism of Actinomycosis. 



This parasite was first discovered by Bollinger in the ox and given 

 the name of actinomyces, or ray fungus, by the botanist Harz. The 

 two most important publications on the subject of the biology of this 

 micro-organism are those of Bostroem and of Wolf and Israel, published 

 in 1890 and 1891, respectively. 



