STREPTOTHRIX GROUP 367 



Insufficient care has been taken in this respect up to the present. 

 Any such organism found should be compared in cultural and 

 pathogenic properties with the human tubercle bacillus, the bovine 

 bacillus of pseudo-tuberculosis, and the various acid-fast organisms, 

 and not simply accepted on tinctorial properties as a tubercle 

 bacillus. 



Acid-fast Streptothrix Group.— Eecently, considerable attention 

 has been given to the group of "higher bacteria" known as the 

 streptothricece. Seen in its mature form, a streptothrix appears to 

 consist of a tangled mass of mycelial threads, some short bacillary 

 forms, and spores. The life cycle is completed by the growth or 

 sprouting of spores by which a mycelium is developed. This branches 

 off in various degrees and directions, and probably sprouts itself, and 

 so produces, with the development arising from spores, a fresh 

 mycelial growth. The mycelium may undergo fragmentation, and 

 thus bacillary forms occur. Streptothrix is usually readily stained 

 by Gram's method, but several species are acid-fast. Foulerton and 

 Price Jones found this to be characteristic of S. Nocardii, S. cwprm, 

 S. horninis (Sabrazes), and S. Eppingeri, in older culture, and then 

 only the mycelial threads and not the spores. Twenty-one other 

 species were not acid-fast.* The germs of streptothrix usually grow 

 better in culture media at 37° C. than at 22° C, and better aerobically 

 than anaerobicaUy. Pigment production occurs in some forms, 

 and certain species liquefy gelatine. One of the best media to use 

 is maltose-peptone agar, but potato, peptone broth, gelatine, or milk 

 are also used. A number of workers have now isolated species of 

 streptothrix from natural media, some of which are declared to be 

 acid-fast. Many of the group are pathogenic to man or animals. 

 S. actinomycis (actinomycosis), S. boms co?nmunis, S. tnadurce 

 (" Madura-foot "), and the disease known as " farcins des boeuf s " are 

 examples. The organisms found in lachrymal concretions, alveolar 

 abscesses, and similar conditions, especially in relation to the jaws, 

 are probably frequently streptothrical in origin. These may gain 

 access to the tissues through carious teeth (by air or food). Infec- 

 tion may also occur through the tonsils, or cutaneously (as in 

 Madura-foot). 



A description of Streptothrix antinomy ces will be found on a 

 subsequent page. Here two forms of Streptothrix isolated by Fouler- 

 ton from cases of disease may be described. 



1. streptothrix luteola (Foulerton). 



Isolated from a case of sloughing keratitis in a girl of 12 years. 



Staining Characteristics. — Stains well by Gram's method in young cultures ; 



* Trans, of the Path. Soc. of London, 1902, vol. liii., pt. i., p. H5. 



