296 ACTINOMYCOSIS AND ALLIED DISEASES. 



colour ; it is pathogenic for guinea-pigs, in which it causes caseous lesions. 

 There is, further, the streptothrix madurae 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. Fur- 

 ther 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 posi- 

 tive 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 streptothrix of Israel and 

 Wolff produces nodular lesions both in rabbits and in guinea- 

 pigs, and a similar result has been obtained with several of the 

 other species of streptothrix mentioned above. 



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 

 cover-glass, dried, and stained with a simple solution of any of 

 the basic aniline dyes, such as gentian-violet, though better 

 results are obtained by carbol-thionin-blue, or by carbol-fuchsin 

 diluted with five parts of water. If the specimen be overstained, 

 it may be decolorised by weak acetic acid. Cover-glass prepa- 

 rations of this kind and also of cultures are readily stained by 



