380 BA CTERIOL OG Y. 



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 saifranin. For the demonstration of the fungus 

 in sections, the method of Mallory gives satisfaction. 

 It is as follows : Stain the section on the side with 



FIG. 65. 



Actinomycosis fungus in pus. Fresh, unstained preparation. Magnified 

 about 500 diameters. 



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 

 central masses and the filamentous threads making up 

 the mass of the mycelium are stained blue ; the club- 

 like extremities of the thread are red. Often the red- 

 stained hyaline material is seen to be penetrated to its 

 extremity by a sharply defined blue thread. 



Cultivation of the fungus from the aetinomycotic pus 



