SUPPURATION AND SEPTIC DISEASES 131 



The Acne Bacillus. 



Unna's B. acnes occurs in many conditions of the skin, 

 such as acne vulgaris. It is Gram-positive and resembles 

 Hofmann's bacillus. Sabouraud regards it as the cause 

 of seborrhcea, but proof of this is thought to be wanting 

 by Cooke and Dold. The organism, which is a facultative 

 aerobe, is most easily grown anasrobically on glucose 

 agar. Raised greyish-white opaque colonies appear in 

 three to five days. Sabouraud' s original medium con- 

 sisted of agar, 15 grammes; peptone, 20 grammes; glycerin, 

 20 grammes; distilled water, 1 litre; and concentrated 

 acetic acid, 5 drops. Fleming's medium (Lancet, April 

 10, 1909) consists of oleic acid (1 to 5 per cent.) in nutrient 

 agar. Western (British Journ. Dermat., January, 1910) 

 and others are of opinion that infection of the sebaceous 

 material with the acne bacillus is a secondary event, and 

 leads, by the irritation caused by its presence, to prolifera- 

 tion of the adjacent epithelium and formation of the 

 comedo. Autogenous acne bacillus vaccine is recom- 

 mended for treatment, but this has apparently failed in 

 seborrhcea (Practitioner, 1910, 526). Cases with much 

 induration are most frequently due to a mixed infection 

 of the acne bacillus and Staphylococcus albus, sometimes 

 with 8. aureus or citreus as well. 



Streptococcus Pyogenes. 



Morphology. In pus a chain may contain up to fifteen 

 elements, but much longer ones of thirty or forty elements 

 are met with in broth cultures, of which the individual 

 cocci may vary very much in size, both large and small 

 cocci being found in one chain. It also sometimes 

 happens that a new chain starts away from one of the 

 cocci in a chain, thus producing branching. The variation 

 in the size of the cocci is also noticed in cultures on other 

 media. The organism is Gram-positive. 



Cultural Characters. The organism grows well in the 

 presence or absence of oxygen. When grown in broth 

 at 37 C., the medium becomes turbid in twenty-four 

 hours; after three or four days multiplication ceases, 

 owing to the production of an inhibitory metabolic 

 substance, but living organisms have been found after 

 ninety days. 



