Microbic Diseases Individually Considered. 279 



formation of pus should be attributed to the acti- 

 nomjces themselves and not to pyogenic bacteria as- 

 sociated with them. Without excluding in all cases 

 the intervention of the hitter w.e think that the pres- 

 ence or absence of suppuration may be dependent 

 upon the animal species infected, as well as on the 

 tissue invaded. Thus, the injection of pure cultures 

 of actinomyces within the abdomen of the rabbit 

 always occasions a suppurative peritonitis; in man, 

 also, the tendency to suppuration is always very 

 marked. Stienon records an instance of cattle af- 

 fected with subcutaneous abscesses of an actinomy- 

 cotic nature. 



The tissue of the organ in which the tumor de- 

 velops shows alterations corresponding to the chronic 

 inflammations set up by its presence ; certain parts 

 become hypertrophied, whilst others diminish or may 

 even disappear. Thus are explained the fibrous in- 

 duration of some of these tumors, the osseous stalac- 

 tites which develop on the maxilla when the invasion 

 begins in the periosteum, and the cavities into which 

 the same bone becomes hollowed when the path- 

 ological process takes place in its center. 



Lesions may appear in the neighborhood of the 

 first affected part ; tbey result from the progressive 

 enlargement of the primary tumor, or from a vascu- 

 lar emigration of the fungus. 



The gradual increase in size of the neoplasm may 

 lead to its extension to the skin or may give rise to 

 distension, thinning, and perforation of the latter in 

 one or more points, from which protrude fungus-like 

 growths which ulcerate and secrete pus mixed with 

 the yellow, pathognomonic grains. 



