MUCOSUS CAPSULATUS GROUP 167 



very cloudy with a silvery deposit at the bottom. The bouillon 

 becomes thickened. Milk is not coagulated, and potato yields 

 a luxuriant yellowish, moist shining growth. 



Pathogenesis. It is possible to cause pneumonia in mice, also 

 septicaemia. Guinea pigs and dogs are susceptible. It may be 

 found in normal mouths. Friedlander's pneumonia is much less 

 frequent than that due to the pneumococcus, but it is very fatal. 

 Members of this group may also be responsible for cystitis, 

 pyelitis, sinusitis and in children pneumonia and pleuritis. The 

 exudate produced by all of them is mucoid, stringy. Anti-bodies 

 are not readily formed against any of the mucosum group so that 

 anti-sera and vaccines are not of great value. 



The Bacterium lactis aerogenes group is a very large one and 

 includes nearly all the forms engaged in milk souring. The 

 ordinary B. lactici is very like the colon bacillus, but is non-motile. 

 It forms lactic acid among its principal products. The most 

 important lactic acid producer related to but not belonging 

 directly in this group, is Bact. bulgaricum of Massol. This is the 

 principal ferment of the eastern sour milks, Kumyss and Yoghurt. 

 Because of the large amount of lactic acid formed by this germ, 

 Metchnikoff has advocated cultures of it and sour milk made 

 by it in the treatment of intestinal putrefaction and fermentation. 

 The Bacterium bulgari^um produces a soft milk curd and an excess 

 of lactic acid and alcohol. The bacteria are non-motile, non- 

 spore-forming, Gram-positive and vary from 21* to 5oju in length. 

 They grow with difficulty in the laboratory, best on milk and 

 whey. Optimum temperature 44C. They form branching fila- 

 mentous colonies. Milk is coagulated in eighteen hours at 44C. 

 and in thirty-six hours at 37C. The clot is not dissolved. Gela- 

 tine is not liquefied. Congeners with this organism are Bac. 

 acidophilus and Bac. acidophil-aerogenes differing from it in fer- 

 mentative powers. 



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