EXPERIMENTAL INOCULATION 337 



streptoth rices as causes of disease is constantly being extended. Wollf 

 and Israel cultivated from two cases of "actinomycosis" in man a strepto- 

 thrix which differs in so many important points from the actinomyces of 

 Bostrbm that it is now regarded as a distinct species. Another species 

 was cultivated by Eppinger from a brain abscess, and called by him 

 "cladothrix asteroides," from the appearance of its colonies on culture 

 media. A case of general streptothrix infection in the human subject 

 described by Stuart M'Donald was probably due to the same organism as 

 Eppinger's. In the tissues it grows in a somewhat diffuse manner, and 

 does not form clubs ; in rabbits and guinea-pigs it produces tubercle-like 

 lesions. Flexner observed a streptothrix in the lungs associated with 

 lesions somewhat like a rapid phthisis, and applied the name "pseudo- 

 tuberculosis hominis streptothricea " ; an apparently similar condition 

 has been described by Buchholz. Berestnew cultivated two species of 

 streptothrix from suppurative lesions, one of which is acid-fast and grows 

 only in anaerobic conditions. Birt and Leishman have described another 

 acid-fast streptothrix obtained from cirrhotic nodules in the lungs of a 

 man. This organism grows readily on ordinary media, forming a white 

 powdery growth which afterwards assumes a pinkish colour ; it is patho- 

 genic for guinea-pigs, in which it causes caseous lesions. There is, further, 

 the streptothrix Madurse described below. 



In diseases of the lower animals several other forms have been found. 

 For example, a streptothrix has been shown by Nocard to be the cause 

 of a disease of the ox," farcin du bceuf," a disease in which also there 

 occur tumour-like masses of granulation tissue. Dean has cultivated from 

 a nodule in a horse another streptothrix, which produces tubercle-like 

 nodides in the rabbit with club-formation ; it has close resemblances to 

 the organism of Israel and Wolff. The so-called diphtheria of calves and 

 " bacillary necrosis " in the ox are probably both produced by another 

 streptothrix or leptothrix, which grows diffusely in the tissues in the 

 form of tine felted filaments. Further investigation may show that some 

 of these or other species may occur in the human subject in conditions 

 which are not yet differentiated. 



Experimental Inoculation. Inoculation of smaller animals, 

 such as rabbits and guinea-pigs, has usually failed to give positive 

 results. This was the case, for example, in the important series 

 of experiments by Bostrom, and it may be assumed that these 

 animals are little susceptible to the actinomyces. The disease 

 has, however, been experimentally produced in the bovine species 

 both by cultures from the ox and from the human subject. 

 Inoculation with the organism of Israel and Wolff produces 

 nodular lesions both in rabbits and in guinea-pigs, while Wright 

 found that characteristic colonies and lesions resulted although 

 the parasite did not grow to any great extent. Several of the 

 other species of streptothrix have been found to possess active 

 pathogenic properties. 



Methods of Examination and Diagnosis. As actinomycosis 



cannot be diagnosed with certainty apart from the discovery of 



the parasite, a careful examination of the pus in obscure cases of 



suppuration should always be undertaken. As already stated, 



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