THE DIAGNOSIS OF ACTINOMYCOSIS Ir5 
III 
THE DIAGNOSIS OF ACTINOMYCOSIS 
Actinomycosis is caused by one of the higher bacteria be- 
longing to the Streptothrices. It is commonly called the “ ray 
fungus’ because of its morphology. It occurs in the tissues 
in small granules which are stellately arranged threads pro- 
jecting outwardly with the ends club-shaped. The positive 
diagnosis of actinomycosis consists, therefore, in finding the 
granules or ray fungus in the affected tissue or its discharges. 
In the case of purulent discharges the suspected material can 
be spread in a thin layer on a piece of glass or on a knife 
blade and examined with a low-power lens (hand lens) when 
the yellowish granules can be detected. In the laboratory the 
morphology of the ray fungus can be studied more accurately 
by placing the discharge on a slide, adding a few drops of 
10% solution of caustic potash, covering with a cover glass, 
and examining with a moderately high-power objective. 
In some cases the affected tissues are firm and must be 
sectioned and stained before making the microscopic exami- 
nation. The stain commonly used for the ray fungus either 
in smears or in sections is carbol fuchsin. The Gram method 
is sometimes used. .Cultures of actinomycosis are not usually 
employed in diagnosis. 
If it is desired to send specimens of suspected ‘actinomy- 
cosis to a laboratory for diagnosis, all or a portion of the affected 
part should be sent fresh and packed in ice. 
