VARIETIES OF ACTINOMYCES. 295 



purpose unopened eggs also, either in the fresh or boiled con- 

 dition, have been used, inoculation being effected by drilling in 

 the shell a small hole which is afterwards closed. The growth 

 on potatoes is somewhat similar to that on agar. 



On gelatin the same tendency to grow in little spherical 

 masses is seen, and the medium becomes very slowly Hquefied. 

 When this occurs the liquefied portion has a brownish colour 

 and somewhat syrupy consistence, and the growths may be seen 

 at the bottom, as little balls, from the surface of which filaments 

 radiate. 



In the cultures at an early stage the growth is composed of 

 branching filaments, which stain uniformly (Fig. 105), but later 

 some of the superficial filaments may show segmentation into 

 go.nidia. True clubs are not formed in cultures, though sHght 

 bulbous thickenings may be seen at the end of some of the 

 filaments. 



Varieties of Actinomyces and Allied Forms. — It is probable that in the 

 cases of the disease described in the human subject there are more than 

 one variety or species of parasite belonging to the same group. Gasperini 

 has described several varieties oi actinomyces bovis according to the colour of 

 the growths, and a similar condition may obtain in the case of the human 

 subject. Furthermore a considerable number of streptothrices have been found 

 in cases of disease in the human subject, the associated lesions varying in 

 character from tubercle-like nodules on the one hand to suppurative processes 

 on the other. The organisms cultivated from such sources differ according to 

 their microscopic characters (for example, some 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 streptothrices as causes of disease is constantly being 

 extended. Wolff and Israel cultivated from two cases of " actinomycosis " in 

 man a streptothrix which differs in so many important points from the actino- 

 myces 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. 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. Quite recently 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 



