422 BACTERIA PATHOGENIC TO MAN 



with some of the cultures relatively extensive lesions, considering the 

 size of the animal. The most extensive lesions showed little progressive 

 tendency, and in only a very few instances did multiplication of the 

 micro-organism in the body of the inoculated animal seem probable. 

 In view of the negative or ambiguous results of those who have inoculated 

 healthy animals with actinomyces directly from the lesions, it would 

 seem that the results of the inoculation of animals with the cultures 

 described in this paper afford as much proof as can be expected from 

 such experiments that the micro-organism in the cultures was identical 

 with the micro-organism in the original lesions. 



I do not accept the prevalent belief, based on the work of Bostroem, 

 Gasperini, and others, that the specific infectious agent of actinomycosis 

 is to be found among certain branching micro-organisms, widely dis- 

 seminated in the outer world, which differ profoundly from actinomyces 

 bo vis in having spore-like reproductive elements. I think that these should 

 be grouped together as a separate genus with the name of nocardia, and 

 that those cases of undoubted infection by them should be called nocard- 

 iosis and not actinomycosis. The term actinomycosis should be used 

 only for those inflammatory processes the lesions of which contain the 

 characteristic granules or "drtisen." That a nocardia ever forms these 

 characteristic structures in lesions produced by it in man or cattle has 

 not been convincingly shown. 



Because the micro-organism here described does not grow well on all 

 the ordinary culture media and practically not at all at room temperature, 

 I do not believe that it has its usual habitat outside of the body. It 

 seems to me very probable that it is a normal inhabitant of the buccal 

 cavity and gastrointestinal tract. 



The cultures are quite resistant to outside influences; dried, they 

 may be kept for a year or more; they are killed by an exposure of five 

 minutes to a temperature of 75 C. 



Occurrence in Animals. Actinomycosis is quite prevalent among 

 cattle, in which it occurs endemically; it is more rare among swine and 

 horses, and is sometimes found in man. The disease is rarely com- 

 municated from one animal to another and no case is known where a 

 direct history of human contagion has been obtained. The cereal 

 grains, which from their nature are capable of penetrating the tissues, 

 have been repeatedly found in centres of actindmycotic infection. This 

 usually occurs in the vicinity of the mouth, where injuries have been 

 accidentally caused. The micro-organism may also be introduced by 

 means of carious teeth. Cutaneous infection has been produced by 

 wood splinters, and infection of the lungs by aspiration of fragments 

 of teeth containing the fungus. The presence of the micro-organism in 

 cereal grains, which was formerly accepted, is denied by Wright and 

 therefore certainly placed in doubt. The further distribution of the 

 fungus after it is introduced into the tissues is effected partly by its 

 growth and partly by conveyance by means of the lymphatics and 

 leukocytes. Not infrequently a mixed infection with the pyogenic 

 cocci occurs in actinomycosis. 



