224 GLANDERS AND ACTINOMYCOSIS. 



small round cells, giant cells, and leucocytes. This tumor 

 eventually undergoes necrosis, breaks down, and discharges 

 on the surface through a sinus. The tumor closely resembles 

 an osteosarcoma in its structure, and for a long time was con- 

 sidered as such. The actinomycetes are found imbedded in 

 this tumor mass. 



In man infection may occur through the mouth, through the 

 respiratory or gastro-intestinal tract, and through the skin. 



Clinical observation of the disease in man has shown that 

 actinomycosis not infrequently occurs in individuals who 

 have been in the habit of chewing wisps of hay or straw, or 

 different kinds of cereals. Certain it is that the disease is seen 

 only in persons who have to do with cattle a great deal and 

 in farmers. In many instances it has been possible to prove 

 the existence of a straw-chewing habit. People who are in 

 the habit of chewing a tooth-pick or some other sharp-pointed 

 or rough object are also liable to the infection because of the 

 presence of some injury of the gum produced by the foreign 

 body in the mouth. The lower jaw is affected more often 

 than the upper. 



Infection through .the skin is not very common. It always 

 occurs through an abrasion or a wound. Running a splinter 

 of wood into the finger or foot is the usual method of infec- 

 tion. 



Infection through the respiratory tract occurs as a rule by 

 inhalation, although the disease may extend from the jaw along 

 the muscles of the neck and into the lungs and pleura. From 

 there it may continue down through the diaphragm and into 

 the abdominal cavity. When the disease appears in distant 

 parts of the body it is due to the rupture of an actinomycial 

 mass into the bloodvessels, a metastasis such as is seen in 

 malignant tumors. Lodgement of the actinomyces in the 

 lung is followed by a fatal bronchopneumonia. 



The gastro-intestinal tract serves as a portal of infection 

 when food containing the actinomyces is eaten. The inspec- 

 tion of cattle is very stringent, and cases of lumpy jaw are 

 always promptly condemned ; but unfortunately some persons 

 are avaricious enough to dispose of such cattle for food, and 

 infection from that source is possible. The disease may 



