222 GLANDERS AND ACTINOMYCOSIS. 



because of its size, is easily detected in the lesions as small 

 sulphur-yellow granules ranging from 0.5 to 2 mm. in diame- 

 ter. When one of these granules is transferred to a slide 

 and examined microscopically (Fig. 91), it is seen to be made 

 up of a central granular mass from which radiate a large 

 number of club-shaped threads. It really consists of three 

 zones : the central granular zone ; next to that a zone com- 

 posed of freely interlacing threads. The free ends of these 

 threads are directed outward to form the third or outer zone, 

 which consists of the club-shaped extremities of these threads. 



FIG. 91. 



Three actinomyces from a case of pulmonary actinomycosis. Below, three finger-like 

 buds and dichomatous branching of actinomyces threads. X 450. (Baumgarten.) 



It is easily stained with the usual anilin dyes, and also by 

 Gram's method. When the organism is to be stained in 

 tissue, picrocarmine gives very good results, the tissue being 

 stained carmine and the actinomyces yellow. Gram's stain, 

 followed by Weigert's method also brings out the organism to 

 good advantage. 



Pure cultures are made from the actinomyces granules. 

 These are removed from the tissues, slightly crushed between 

 sterile glass slides, and transferred to the culture-medium. 

 The organism is strongly aerobic, developing rapidly at the 

 room temperature on all the usual media. A strictly anaero- 

 bic variety has also been described. 



