CHAPTER XIII. 



ACTINOMYCOSIS AND ALLIED DISEASES. 



Actinomycosis is the most important of the group of diseases pro- 

 duced by organisms of the genus streptothrix (Cohn) or discomyces 

 (Eivolta and French writers). It occurs in man in common with 

 certain of the domestic animals, though it is more frequent in 

 the latter, especially in oxen, swine, and horses. The parasite 

 was first discovered in the ox by Bollinger, and described by 

 him in 1877, the name actinomyces or ray fwngus being from its 

 appearance applied to it by the botanist Harz. In 1878, Israel 

 described the parasite in the human subject, and in the following 

 year Ponfick identified it as being the same as that found in the . 

 ox. It is, however, to be noted that the term " actinomyces," as 

 originally used, does not represent one parasite but a number of 

 allied species, as cultures obtained from various sources have 

 presented considerable differences. Moreover, it has been found 

 by Lignieres and Spitz that in a common type of actinomycosis 

 in the ox the colonies are formed not by a streptothrix but by a 

 bacillus to which they have given the name of actinobacillus. 

 The term " actinomycosis " accordingly does not represent a 

 specific disease, but may conveniently be retained for infections 

 in which the parasite forms " granules " or colonies with a more 

 or less radiate appearance at the periphery. Such infections 

 have now been shown to be of comparatively common occurrence. 

 Further, other distinct species of streptothrix, without the 

 characteristic arrangement, have been cultivated from isolated 

 cases of disease in the human subject where the lesions resembled 

 more or less closely those of actinomycosis. In one or two 

 instances the organism has been found to be "acid-fast," 

 and there is no doubt that the actinomyces group is closely 

 related through intermediate forms with the tubercle group 

 {vide p. 269). 



Naked-Eye Characters of the Parasites. — The actinomyces 

 grow in the tissues in the form of little round masses or colonies, 



