PLATE XXII. 



FIG. i. -BACILLUS OF RHINOSCLEROMA. 



From a streak culture on agar, of forty-eight hours' growth, incubated at 37 C. 



Carbol fuchsine, washed in dilute acetic acid. The figure shows a group of bacilli united 

 into a zooglcea by an abundant ground substance which is faintly stained with the dye. 

 The micro-organism consists of spherical elements occurring 'singly, but most frequently in 

 pairs or short chains. Rod forms may also be met with. 



As showing the essential similarity of ground-substance, or gloea, and, that which con- 

 stitutes a bacterial capsule, it will be noticed that whilst at the periphery, where active 

 multiplication is proceeding, the bacilli lie closely embedded in this substance, more 

 centrally, where the latter has accumulated in larger amount, it has parted into areas 

 appertaining to definite groups, showing the divided share which the organisms have taken 

 in its production. At the lower end of the figure, near its middle, there is a diplo-bacillus 

 quite isolated from the neighbouring mass, and furnished with a capsule proper to itself. 



FIG. 2. STREPTOTHRIX ACTINOMYCES. 



Broth culture, of seven days' age. incubated at 37 C. 



In broth the growth occurs as small spherical colonies, which are best examined by being 

 teased out on a cover-glass after haying been washed in distilled water. The preparation is 

 allowed to dry and may be then stained with carbol fuchsine or aqueous solution of gentian 

 violet ; in the former case the subsequent washing is carried out with acidulated water, in the 

 latter with tap water, or. what is better, with a i in 10,000 solution of caustic potash, 

 followed by tap water. 



The culture consists solely of long, interlacing, slightly wavy filaments which give off 

 lateral shoots. The branches vary in length according to their age, taking, on their first 

 appearance, the form of minute excrescences. 



Cultures of the streptothrix Madura? (the cause of mycetoma or Madura disease) are indis- 

 tinguishable in microscopic features from streptothrix actinomyces. 



As found in the tissues of oxen affected with actinomycosis, the filaments, as a rule, 

 terminate in clubbed enlargements, and radiate from a central mass. In the lesions of the 

 human subject the clubs are by no means regularly present, nor is a radial disposition of the 

 filaments always obvious. 



Such differences possibly indicate that the streptothrix causing the disease known clinically 

 as actinomycosis in man and the lower animals is not always identical, the existence of 

 pathogenic varieties (which have received special names) having been demonstrated by 

 means of artificial cultures. 



Owing to its anomalies, the classification of this group of organisms has been long a 

 subject of controversy, which has been terminated, at least for a while, by raising it into a 

 distinct class of fungi under the name of streptothricise. 



The group includes non-pathogenic as well as pathogenic forms, and comprises micro- 

 organisms which, like hyphal-fungi or moulds, form a mycelium of branching filaments 

 originating from spherical spores ; certain of the filaments (like the aerial hyphse of moulds) 

 ru>e into the air from the mycelium and produce at their extremities chains of spherical 

 elements comparable to spores, though of a different morphological nature from, e.t;,, the 

 endo-spores of bacilli. 



