330 ACTINOMYCOSIS AND ALLIED DISEASES 



form "clubs" whilst others do not), according to their conditions of 

 growth, staining reactions, etc. Of these only a few examples may here 

 be mentioned, but it may be noted that the importance of the strepto- 

 thrices as causes of disease is constantly being extended. A species of 

 streptothrix 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 pathogenic for guinea-pigs, in which it causes 

 caseous lesions. There is, further, the streptothrix rnadurse 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 

 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 

 "baeillary 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. 



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 may be recognised with the 

 naked eye, especially when some of the pus is spread out on a piece of 

 glass. If some of these are washed in salt solution and examined unstained, 

 the clubs, if present, are at once seen on microscopic examination. 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 preparations of this kind, and also of cultures, are readily 

 stained by these methods, but in the case of sections of the tissues, Gram's 

 method, or a modification of it, should be used to show the filaments, etc., 

 a watery solution of acid fuchsin being afterwards used to stain the clubs. 

 In the case of the disease in the ox the clubs are strikingly demonstrated 

 by staining with carbol-fuchsin and then decolorising with picric alcohol ; 

 or the preparation may be decolorised with 1 per cent, sulphuric acid and 

 then contrast-stained with methylene-blue. 



