408 ACT1NOMYCOSIS 



stubble fields. In horses the disease has been observed in the tongue, 

 lymph glands, etc. A fibrous cord in a horse, seen in 1908 by the 

 author in a dissecting-room subject, was found to be due to actinomy- 

 cosis. Cattle and hogs likewise contract actinomycosis from castration 

 wounds. 



In man, as in cattle, the ray fungus disease generally makes its 

 entrance through wounds of the mouth. It has been known to follow 

 the habit of chewing grain or picking the teeth with straws. Pieces 

 of barley and pieces of straw have been found in decayed teeth from 

 which the disease evidently started. In man, actinomycosis frequently 

 begins in the intestines, where also its principal lesions develop and 

 from which place it generally invades the liver. 



Microscopically, parts infected with actinomyces show a gran- 

 ulation tissue composed of lymphoid and epithelioid cells, and also 

 polynuclear giant cells. The latter are generally less regular in out- 

 line than those found in tuberculosis. External to the cellular tissue 

 a zone of fibrous tissue is found. Actinomycotic tissue also shows a 

 more or less pronounced infiltration, with ordinary polynuclear 

 leukocytes ; basophilic plasma cells are likewise seen. 



Systematic Classification and Morphology. The microorganism 

 causing the disease actinomycosis is variously classified by different 

 authors. Some look upon it as a streptothrix and class it with the 

 so-called pleomorphous bacteria, others class it among the trichomy- 

 cetes (hair fungi), and still others place it in a class by itself, inter- 

 mediate between the bacteria (schizomycetes) and the lower moulds 

 (trichomycetes). Quite a number of species of actinomyces exist 

 (generally as saprophytes) in the outside world, and only occasionally 

 invade the animal tissues, there to lead a parasitic existence. 



Microscopic Examination of Fresh Material. In making a micro- 

 scopic examination for the actinomyces, or ray fungus, it is best to 

 scrape some of the purulent material from an actinomycotic ulcer or 

 abscess with a small scalpel and to spread this material on a slide, 

 where it is covered with a cover-glass without making any pressure. 

 If the preparation is now held against a dark background the so- 

 called actinomyces granules can frequently be recognized with the 

 naked eye. The majority are from 0.1 to 0.2 mm. in diameter and 

 cannot be seen without magnification; but some are 0.5 mm. and 

 more in size, and these appear as small yellowish, yellowish-green, or 

 yellowish-brown granules to the naked eye. As these masses of fungi 

 grow larger and older they generally appear more highly colored and 

 more pronouncedly yellowish brown. If the preparation is now 

 examined under the low power of the microscope the characteristic 

 rosettes are seen, formed by club- or pear-shaped bodies arranged 

 in a radiating manner around a common centre. From this typical 

 arrangement, always shown in pus or tissues, the name actinomyces, 

 or ray fungus, is derived. The rosette of clubs is frequently surrounded 

 by lymphoid cells, polynuclear leukocytes, or giant cells. Sometimes 



