644 



Actinomycosis. 



and subsequently assume different shades of yellow and blackish-gray 

 (commonest form), varying from light yellow to yellowish-brown, and 

 in rare cases, a blackish-gray. These granules or colonies have, as 

 a rule, an irregular or warty surface ; the older structures unite to 

 form masses which are visible to the unaided eye and bear some re- 

 semblance to a blackberry. They are firm, not easily crushed, and 

 sometimes hard as a result of calcification. 



In each granule these may usually be recognized l)y a central por- 

 tion consisting of filaments, rods and spores and a peripheral portion 

 composed of the cluli-shaped ends of the parasite. 



The individual filament consists of a membrane enclosing a ])ody 

 of protoplasm and shows a distinct tendency to dichotomous branching, 

 each branch in its turn possessing the same habits. Transverse parti- 

 tions divide these filaments into short rods and the latter seem to be 

 divided by similar partitions into coccus-like structures, the so called 



Fig. 99. Streptothrix Actino- 

 myces. Agar culture in dilute 

 fuchsin solution. 



Fig. 100. Actinomyces colonics 

 and single club-shaped individ- 

 uals. From tumor of maxilla ; 

 examined in caustic ])otash so- 

 lution. 



Spores which, however, may also be found in the interior of the filament 

 (according to Domec, at the ends only), thus producing torula-like 

 structures. (These spore-like bodies, unlike the spores of bacteria or 

 those of some mold fungi, e. g., those of the Oidium species, are readily 

 stained with aniline dyes.) The so called spores, after separation from 

 the filament, develop into rods which finally form new branching 

 filaments. 



Filaments thus developed intertwine aiul produce mycelium-like 

 colonies, on the periphery of which the radially-arranged club-shaped 

 ends project. In the old colonies in particular, these club-shaped ends 

 constitute a continuous envelope surrounding the central mycelium, 

 thus giving the colony the characteristic mulberry appearance. In 

 colonies obtained from infected tissue the envelope referred to is 

 usually ])roken and interrupted at some point, from wliich a thick 

 strand of filaments projects from the central mass and to a certain 

 extent penetrates the surrounding tissue walls (radical filaments). The 

 club-shaped ends which are not infrequently constricted so as to resemble 

 the fingers of a hand were formerly looked upon as buds (gonidia) 

 (Harz, Bollinger, Johne, Ponfick). At present, however, the view of 

 Bostrom is probably looked upon as more correct. According to this 

 view these so called gonidia are the result of a specific hyaline degenera- 



