METHODS OF EXAMINATION AND DIAGNOSIS 327 



form clubs ; in rabbits and guinea-pigs it produces tubercle-like lesions. 

 Flexner observed a streptothrix in the lungs associated with lesions some- 

 what 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 pathogenic for 

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

 streptothrix rnadurae 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 boeuf," 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 

 nodules 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 

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

 form of fine 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, 

 the colonies can be recognised with the naked eye, especially 

 when some of the pus is spread out on a piece of glass. If one 

 of these is washed in salt solution and examined unstained, the 

 clubs, if present, are at once seen on microscopic examination. Or 

 the colony may be stained with a simple reagent such as picro- 

 carmine, and mounted in glycerin or Farrant's solution. To 

 study the filaments, a colony should be broken down on a cover- 



