458 FUSIFORM ANAEROBIC BACILLI 



conditions, and the best media are those consisting of a 

 mixture of serum or blood and agar (1 : 3). The organisms 

 form small rounded colonies of whitish or yellowish colour, 

 somewhat like those of a streptococcus, but rather felted in 

 appearance on the surface. Injections of pure cultures in 

 animals sometimes produce suppuration but never necrosis 

 (Ellermann). Tunnicliffe finds that the spirochsetes are only 

 stages in the development of fusiform bacilli, as cultures which 

 at an early stage show only fusiform bacilli afterwards contain 

 spirochastes, and intermediate forms can be found. There seems 

 to be no doubt that in cultures the bacilli grow out into long 

 filaments which may have an undulated appearance ; but it is 

 doubtful whether these are to be regarded as true spirochsetes, 

 and still more whether they are the same spirochsetes as those 

 seen in the lesions in association with the bacilli. It is also 

 to be noted that fusiform bacilli are sometimes present in the 

 secretions of the mouth in normal conditions, and may occur in 

 increased numbers in true diphtheria. 



