ACTINOMYCOSIS 257 
up of rosettes varying in size from 10 to 200y. in diameter, the average 
size ranging from 30 to 404. This fungus can be cultivated on arti- 
ficial media. It stains somewhat feebly with the aniline dyes. 
The rosettes are composed of a number of club-shaped structures 
(rays), radiating from the central mass which is composed of the 
mycelial part of the organism. The club-shaped bodies vary in size 
but usually they are from 1 to 10¥-long.. The rays are connected with 
the central portion by fine thread-like structures which are not 
Fie. 54. PHOTOGRAPH OF A YOUNG ACTINOMYCOTIC GROWTH UNDER LOW POWER, 
SHOWING CLUMPS OF THE ACTINOMYCES. 
readily demonstrated. In tearing or crushing the rosette, the clubs 
break off at or near their junction with the mycelial threads. Some 
investigators have mentioned a polymorphous form of actinomyces in 
which coccoid and rod-shaped structures are found. These are doubt- 
less the ends of the clubs which first appear in focusing on a rosette. 
‘The natural habitat of this organism is said to be certain plants. 
According to Brazzola, they vegetate on the grasses, chiefly on 
Hordeum murinum. He discovered quantities of it between the 
vegetable fibres of barley which were imbedded in the gums of ani- 
