Actinomycosis. Lumpy-Jaw. 37 



mogenus and A. Gruberi the last two being very destructive to 

 Guinea-pigs. These are probably interchangeable according to 

 the environment. 



The organism is both aerobic and anaerobic, and forms numer- 

 ous spores by the continuous transverse division of the filaments. 

 It was first ranked as a mould, later, by reason of its pseudo . 

 branching, as a cladothrix (Bostrom) or streptothrix. Sauva- 

 geau and Rabais however consider it as one of the higher fungi 

 and create for the class the generic name of Oospora. Crook- 

 shank assigns it to a place intermediate between the higher 

 fungi and bacteria. 



Pathological Anatomy. Around the actinomyces growth 

 there is a great accumulation of lymphoid and epithelioid cells, 

 with a few giant cells, and these in turn are surrounded by a 

 greater or less abundance of firm, fibrous cicatricial ti.ssue. Ex- 

 cept for the presence of the actinomyces, the neoplasm bears a 

 strong resemblance to sarcoma. When the fibrous formation is 

 defective the mass is soft, friable and mainly cellular ; when 

 abundant it may attain the consistency of cartilage. In the 

 bones of the face or jaw the neoplasm forms sarcomatous masses 

 filling a series of excavations in the interior of the bone, which, 

 greatly enlarged and distorted, covers these masses more or less 

 perfectly with thin osseous walls. When invaded by pus mi- 

 crobes, as in cases of ulceration of the investing tissues, the 

 neoplasm may be more or less surrounded or permeated by sup- 

 purating foci, the products escaping through one or more fistulae. 

 Often the pus is formed in the centre of the tumor which still 

 shows an extending surface of granulation tissue. 



The disease advances by gradual invasion of all surrounding 

 tissues, taking them into its substance after the manner of a car- 

 cinoma, and as it advances the neoplasm may undergo contraction 

 behind into a simple cicatricial mass, so that there is a slow 

 migration from place to place. In this process phagocytosis fills 

 an important r61e, and if active enough will sometimes destroy 

 the parasitic growth and determine a spontaneous recovery. 



It should be noted that the spores and rod-hke products of the 

 microbe and even the club-shaped endings, sometimes enter the 

 leucocytes (wandering lymph cells) and are carried to distant 

 points, to start new colonies. 



