ACTINOMYCOSIS 



155 



of large semisolid tumefactions usually in the upper air pas- 

 sages or their neighboring tissues and in the lungs. It may 

 spread under the skin or into organs. The bones of the jaw 

 are usually involved. Any bone in the path of progression 

 of the disease may be infiltrated. The organisms causing it 

 belong to the higher bacteria, and are called Streptothrix 

 actinomyces, Actinomyces bovis or ray fungus, because of their 

 tendency to spread out in rays. The organism enters by 

 way of the mouth or nose into cracks or wounds. Associa- 



FIG. 48. Actinomyces fungus ("ray fungus"): left, as seen in tissues 

 under low magnifying power; right, a fungus mass examined fresh under 

 higher magnifying power. (Abbott.) 



tion with, or eating uncooked meat of animals having the 

 disease is the method of infection in man. The disease 

 remains infectious as long as there are open lesions, dis- 

 charging bacilli. No quarantine is needed provided the 

 patient is under proper supervision. 



When the germs enter they start to proliferate and excite a 

 nodule not unlike that of tuberculosis. It spreads by con- 

 tinuity outward and involves adjoining structures. The 

 center of the nodules softens into caseous matter in which 

 small white or gray masses of the bacterial growth may be 



