70 CLINICAL BACTERIOLOGY AND H^mAtOLOGY 



ACTINOMYCOSIS, OR STREPTOTHRICOSIS 



Actinomycosis is very closely allied to tuberculosis ; the lesions 

 appropriate to the two diseases are almost identical in histological 

 appearance, and the granuloma which occurs in actinomycosis 

 goes on to fibrosis or to the formation of "cold abscesses" just 

 as a tubercle may do. The formation of fibrous tissue is most 

 marked in cattle, and in them the disease is more chronic ; 

 suppuration is more common in man, and the disease runs a more 

 rapid course. 



The pus from an actinomycotic abscess is often viscid, and 

 contains a greater or smaller number of small greenish, yellow, or 

 brownish nodules. They are about as large as the head of a very 

 small pin, and are quite opaque ; under the low power of the 

 microscope such a granule has a coarsely granular appearance, 

 and looks something like a raspberry. If nodules presenting 

 these appearances are found in any specimen of pus, whatever 

 be its origin, a careful microscopic examination should be made 

 to determine its nature. This is not difficult. 



Method. — Place some of the pus which contains these granules 

 on a clean slide, and press another slide upon it so as to crush 

 the granules; dry, fix, and stain by Gram's method. Do not 

 counter-stain. 



Tumours removed or incised at an operation, or organs removed 

 at a post-mortem examination, should have their cut surfaces 

 rubbed upon the surface of a slide, and the film thus obtained 

 treated in a similar way ; or they may be scraped, and the 

 scrapings spread on a slide. Sections may also be cut, but are 

 not usually necessary for the diagnosis. 



Examination of the Specimens. 



Actinomycosis of cattle is caused by the ray fungus, an 

 organism which derives its name from the star-shaped colonies 

 which it forms whilst growing in the tissues. It consists of two 

 chief parts ; the central portion of the colony is formed of a 

 network of narrow filaments, which have a radial arrangement 

 at the periphery (Plate II., Fig. 6). In this part small bodies 

 which have the appearance of cocci may often be seen. The 

 outer zone consists of the clubs which (when present) are so 

 characteristic. These clubs are flask-shaped expansions of the 



