296 ACTINOMYCOSIS AttD ALLIED DISEASES 



in rabbits and guinea-pigs it produces tubercle-like lesions. Flexner 

 observed a streptothrix in the lungs associated witb 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 

 pathogenic 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 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 streptothrix 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 

 picrocarmine, and mounted in glycerin or Farrant's solution. 

 To study the filaments, a colony should be broken down on a 



