BACILLUS ENTBRITIDIS SPOROGENES 443 



retain their vitality for six weeks or more. Shake cultures 

 in grape-sugar gelatine show similar appearances, but 

 liquefy rather less slowly. The earliest colonies are visible 

 in two days, and they become somewhat irregular in shape. 



Growth in Milk. — Milk cultures incubated at 37° C, in 

 an atmosphere free from oxygen, coagulate energetically in 

 from one to four days, usually in two. A firm white curd 

 separates from a clear whey, and undergoes no further 

 breaking up or digestion. A strongly acid reaction is pro- 

 duced, and the cultures have a faint sour smell, sometimes, 

 but not always, distinctly like butyric acid. Tested volu- 

 metrically, the amount of acid produced is not large. 



Pathogenesis. — Subcutaneous inoculation of guinea-pigs 

 with recent milk cultures produces in some cases intense 

 spreading haemorrhagic oedema and necrosis, and death in 

 twenty-four hours. In other cases it is not pathogenic. 



Black Torula {Saccharomyces niger). — This yeast is fre- 

 quently met with in the air. Cultural characters : 



Gelatine Plates and Streaks. — Forms a'heaped-up black 

 mass. 



Potatoes and Bread. — Grows as a sooty black crust, with 

 a dry furrowed surface. 



Bacillus Erytlirosporus. — This organism, which occurs in 

 water, etc., is a slender bacillus, which may form chains, 

 and is very motile. From two to eight oval spores appear 

 at the ordinary temperature in each rod, which may extend 

 beyond the walls of the bacillus. They are characterised 

 by their reddish colour ; even when the bacillus is stained 

 with methylene-blue, the spores retain their reddish colour. 

 Cultural characters : 



Gelatine Plates. — Whitish colonies are formed, which 

 gradually spread over the surface; around them in the 

 gelatine a peculiar fluorescence appears. The centres of 



