ACTINOMYCOSIS, OR STREPTOTHRICOSIS 77 



resist decolorization for a longer period than the tubercle 

 bacillus. This has been denied, but I have personally found it 

 to be the case with all the specimens I have been able to 

 examine. Perhaps the difference of opinion arises from the 

 fact that only young bacilli from the edge of the lesion retain 

 their staining characters fully, the older ones being readily 

 decolorized by acid and being Gram-negative. According to 

 Baumgarten, if the material be stained with aniline violet for 

 five minutes in the cold and decolorized with a mixture of 

 i c.c. of nitric acid and 10 c.c. of absolute alcohol, leprosy 

 bacilli are stained violet and tubercle bacilli decolorized. As 

 a matter of fact, the difficulty seldom arises, but, if it does, 

 recourse should be had to animal experiments. The leprosy 

 bacillus does not infect the guinea-pig'. 



ACTINOMYCOSIS, OR STREPTOTHRICOSIS 



Actinomycosis is very closely' allied to tuberculosis; the 

 lesions appropriate to the two diseases are almost identical in 

 histolog'ical 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 granu- 

 lar appearance, and looks something like a raspberry. If 

 nodules presenting these appearances are found in any speci- 

 men 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 counterstain. Examine also a wet unstained granule 

 after crushing it between slide and cover-glass. 



Tumours removed or incised at an operation, or organs 



