CHAPTER XXXVII. 



ACTINOMYCOSIS. 



Occurrence and Historical. Actino mycosis is a chronic infectious 

 disease occurring principally in cattle and swine, also in man and 

 more rarely in horses and sheep; occasional cases have been observed 

 in deer, elephants, dogs, and cats. It is caused by a microorganism 

 known as the actinomyces (actis ray; mykos, fungus), or ray 

 fungus. Its growth in the tissues of susceptible animals leads to 

 the formation of frequently large, granulomatous, and fibrous tumor 

 masses. The disease in cattle has been known for a long time as 

 lumpy jaw, wens, cancer of the tongue, osteosarcoma, etc. It is 

 now known that Langenbeck, as early as 1845, saw the characteristic 

 ray fungi in a human affection (then mistaken for osteosarcoma). In 

 fact, he gave a picture of the organism, however, without recognizing 

 its nature. In 1848 Lebert again furnished drawings of the ray 

 fungus, and in 1868 Rivolta described it clearly from a case of lumpy 

 jaw in cattle. In 1876 Bellinger recognized the parasitic nature of 

 the actinomyces, and Hartz, a botanist, studied it from the biologic 

 standpoint. A little later the etiology of the disease in man was 

 established by Israel. Actinomycosis is distributed over the entire 

 world, and the fungus is undoubtedly very prevalent in nature, where 

 it is found on grasses. It is probably always contracted by the 

 entrance of the bearded grains of barley, oats, wheat, etc., which 

 carry the fungus into a wound of the buccal or respiratory mucosa. In 

 fact, such evidently infected vegetable parts are very frequently found 

 in actinomycotic lesions, particularly in those of the tongue in cattle. 

 As early as 1882 Johne observed barley hulls infected with actino- 

 myces in the tonsils of hogs, and he expressed the belief that grains 

 of cereals acted as the infection carriers of the disease. It is not yet 

 definitely settled whether actinomycosis in man and animals is due 

 to the same species of ray fungus or whether there are several species 

 or at least several varieties. There is no evidence that actinomycosis 

 is ever spread by direct or indirect contagion from animal to animal 

 or from animal to man; it is, so far as is known, only contracted 

 through infected vegetable parts gaining entrance into the tissues 

 of a susceptible being. 



Pathologic Changes. The ray fungus after entering into and 

 multiplying in the body leads to a chronic inflammatory reaction with 

 considerable new formation of tissue. The granulomatous masses 

 may assume a very large size and appear like true neoplasms or 



