ACTINOMYCOSIS, OR STREPTOTHRICOSIS 6j 



in the fungus present. The organism in bovine actinomycosis is 

 the ray fungus, which is described above ; but in man there are 

 numerous species of fungus which can bring about infection and 

 cause the disease known clinically as actinomycosis : this disease 

 is therefore not a specific entity, due to a single cause, but £ 

 group of allied diseases, just as suppuration is. The organisms 

 in question are all members of the genus Streptothrix, and consisi 

 of long filaments of mycelium, which differ from the bacteria ir 

 showing true branching and in breaking up into " chain spores,' 

 resembling chains of cocci. The different species vary verj 

 greatly in cultural characters, but there are also marked 

 differences in the appearances met with in films of pus, etc. Ir 

 what may be regarded as typical cases, the nodules described 

 above, when flattened out and stained by Gram's method, show a 

 central portion consisting of a tangled mass of narrow mycelial 

 threads, some of which may show the degeneration 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 uf 

 more than half the field of an oil-immersion lens, so that it is bes1 

 to search for them in Gram specimens (not counterstained) with a 

 low power, and to turn successively the J and -Jj- on to any smaL 

 violet masses which may be seen. In other cases the fungus wiL 

 assume the form of threads in masses without any definite 

 arrangement, 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 diagnosis, 

 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. 



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 oi 

 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 



5—2 



