ACTINOMYCOSIS. 209 



localities there are produced considerable enlargements 

 which are sometimes dense and fibrous (wooden tongue) 

 and sometimes suppurative. In sections of these nodular 

 formations small yellowish granules surrounded by some 

 pus can be found. These granules when viewed beneath 

 the microscope exhibit a peculiar rosette-like body the 

 ray-fungus or actinomyces. 



The fungus is of sufficient size to be detected by the 

 naked eye. It can be colored, in sections of tissue, by 

 the use of Gram's method, or better by Weigert's fibrin 

 stain. Tissues pre-stained with carmin, then stained by 

 Weigert's method, give beautiful pictures. 



The entire fungus-mass consists of several distinct 

 zones embracing entirely different elements. At the 

 centre of the mass there is found a granular substance 

 containing numerous bodies resembling micrococci. Ex- 

 tending from this centre into the neighboring tissue is a 

 radiating, apparently branched, thickly-tangled mass of 

 mycelial threads. These threads seem to terminate in 

 a zone of conspicuous club-shaped radiating forms which 

 give the colonies the rosette-like appearance. The cells 

 of the tissues affected and a larger or smaller collection 

 of leucocytes form the surrounding resisting tissue-zone. 



The degree of chemotactic influence exerted by the 

 organism seems to depend partly upon the tissue affected 

 and partly upon the individuality of the animal. When 

 the animal is but slightly susceptible, and when the 

 tongue is the part affected, the disease is characterized 

 by the production of enlargement due to the formation 

 of cicatricial tissue. If, on the other hand, the animal 

 is highly susceptible or the jaw is affected, the chief 

 symptom is suppuration, with the formation of cavities 

 communicating by sinuses. 



Before the nature of the affection was understood it 

 was confounded with various diseases of the bones, prin- 

 cipally with osteosarcoma. 



From the tissues primarily affected the disease spreads 

 to the lymphatic glands, and not infrequently to the 



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