ACTINOMYCOSIS, OR STREPTOTHRICOSIS 7Q 



show a central portion consisting of a tangled mass of nar- 

 row mycelial threads, some of which may show the degenera- 

 tion into chain spores, and look like streptococci, whilst there 

 may or may not be a peripheral portion showing a radial 

 arrangement (Plate II., Fig. 6, which was drawn from a 

 remarkably perfect specimen). These colonies vary greatly 

 in size, but do not usually fill up more than half the field of an 

 oil-immersion lens, so that it is best to search for them in 

 Gram specimens (not counterstained) with a low power, and 

 to turn successively the J and & on to any small violet masses 

 which may be seen. In some cases the fungus will assume 

 the form of threads in masses without any definite arrange- 

 ment, and in others the threads will be isolated; in either 

 case it will usually be possible to find threads showing true 

 branching or chain spores, and this is sufficient for the diag- 

 nosis. In yet others the bulk of the mycelium splits up into 

 short lengths greatly resembling bacilli, and when this happens 

 the diagnosis may be missed unless a careful search happens to 

 reveal an unbroken piece of mycelium (Plate IV., Fig. i). 



Cultures are usually difficult to prepare, and are not much 

 help in the diagnosis. They may be required for the prepara- 

 tion of a vaccine. 



The importance of making this examination as a routine 

 method in all cases in which the diagnosis is not absolutely 

 clear must be strongly urged on all practitioners, since an 

 accurate diagnosis of actinomycosis may be followed in many 

 cases by a cure by means of large doses of iodide of potassium. 

 Actinomycosis has a habit of turning up when least expected ; 

 thus, I have found it accidentally in three cases in the sputum 

 where the true diagnosis was not suspected; once in an 

 enlarged tonsil; once in an apparently typical case of cancer 

 of the breast, etc. 



The films should be carefully examined for the presence of 

 these structures. Clubs are often not in the pus, and their 

 absence does not tell against the diagnosis; the dense felted 

 network of filaments retaining Gram's stain is what is to be 

 looked for, and its presence is quite sufficient for a diagnosis. 

 Fortunate specimens may show a complete colony, with its 

 irregular network in the centre and the radial arrangement 

 of the fibres on the periphery, or there may be mere fragments 

 of mycelium. 



