Morphology 733 



widely in nature seems to be indicated by the fact that cases of 

 infection have been known to occur from the spines of barley and 

 other cereals. Berestnew* succeeded in isolating the organisms from 

 hay and straw. 



Morphology. — A complete ray-fungus consists of several distinct 

 zones composed of different elements. The center is composed of 

 a granular mass containing numerous bodies resembling micro- 

 cocci or spores. Extending from this center into the neighboring 

 tissue is a radiating, branched, tangled mass of mycelial threads. 





Fig. 29g. — Colony or granule of actinomyces in a section throuuh a lesion 

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

 cells surrounding the colony (Wright and Brown). 



In an outer zone these threads are seen to terminate in conspicuous, 

 club-shaped, radiating forms which give the colonies their rosette- 

 like appearance. The clubs are inconspicuous in the human lesions 

 of the disease. 



The pleomorphism of the organism and the branched network 

 it forms class it among the higher bacteria in the genus Actinomyces. 

 When the clumps formed in artificial cultivations of the parasite 

 are properly crushed, spread out, and stained, the long mycelial 

 threads, 0.3-0.5 fi in thickness, occasionally show flask- or bottle- 

 like expansions — the clubs — at the ends. These probably depend 

 * "Centralbl. f. Bact.," etc., Ref., 1898, No. 24. 



