Morphology 



777 



of actinomycosis, was widely distributed in nature upon vegetation 

 generally and grains particularly, and had the cultural and biological 

 pecuUarities ascribed to it, but was not the cause of actinomycosis, 

 but an accidentally and commonly present contaminating organism. 



The true cause of the disease, the real actinomyces was the diffi- 

 cultly cultivable organism of Wolff and Israel. 



The organism of Bostrom is placed by Wright in the genus Nocar- 

 dia. A careful perusal of Wright's paper will convince most readers 

 of the probable correctness of his views which are followed in the 

 succeeding text. 



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Fig. 306. — Colony or granule of actinomyces in a section through a lesion 

 showing the Gram-stained filaments and hyaline material and also the pus- 

 cells surrounding the colony (Wright and Brown). 



Distribution. — ^The actinomyces is known only as a parasitic 

 organism associated with actinomycosis. 



Morphology. — When an actinomyces grain or ray-fungus is ex- 

 amined in a section of tissue it is found to consist of several distinct 

 zones composed of different elements. The center consists of a granu- 

 lar mass containing numerous bodies resembling micrococci or spores. 

 Extending from this center into the neighboring tissue is a 

 branched, tangled mass of mycelial threiads. In an outer zone these 

 threads are seen to terminate in conspicuous, club-shaped, radi- 

 ating forms which give the colonies their rosette- like appearance. 



