368 BACTERIOLOGY. 



or both, and they may show branching. Sometimes the 

 free ends of the threads are only slightly or not at all 

 swollen. 



These mycelia the actinomyces may be stained by 

 the ordinary aniline dyes, or by the Weigert or th 

 Gram method, though by either of these procedures its 

 full structure is not, as a rule, brought out. The reason 



FIG. 



Actinomycosis fungus in pus. Fresh, unstained preparation. Magnified 

 about 500 diameters. 



for this is that the terminal bulbs are not due to enlarge- 

 ment of the thread itself, but rather to a colloid degen- 

 eration of its enveloping sheath. This colloid matter, 

 having different microchemical reactions from the 

 enclosed thread, requires different reagents to stain it. 

 The entire structure may be seen when the fungus is 

 stained first by the Gram method, and subsequently with 

 eosin or saffranin. For the demonstration of the fungus 

 in sections, the method of Mallory gives satisfaction. 

 It is as follows ; Stain the section on the slide with 

 gentian-violet ; clear and dehydrate with aniline oil in 

 which a little basic fuchsin has been dissolved ; remove 

 the aniline oil-fuchsin with xylol, and mount in xylol 

 balsam. In sections treated in this way the coccus-like 



