AEROBIC SPORE-BEARING NON-PATHOGENIC BACTERIA 287 



friable scum forms which is soon precipitated. In many cul- 

 tures the reaction is acid. Reaction alkaline in the majority of 

 cultures. 



Lactose. Turbidity in bowl with scum formation. Arm 

 clear. Reaction alkaline. 



Thermal death point. The spores survive steaming one hour 

 in the Arnold sterihzer and autoclaving at 19 pounds pressure. 

 Killed by 20 pounds pressure. 



1/ 



Bacillus alholactus Migula 1900 



This organism was apparently first obtained in pure culture 

 in 1887 by Loeffler who found it in boiled milk which had soured 

 and clotted and who named it Bacillus lactis-alhus. It is possibly 

 identical with Bacillus corrugatus Migula (1900) (Bacillus No. 

 II Fliigge), with Bacillus bernensis Lehmann and Neumann, 

 (1901) and with the organism described recently by Neide as 

 Bacillus teres which was also obtained from boiled milk which 

 had subsequently soured. It is common in boiled milk in 

 Baltimore and produces the souring, clotting, and subsequent 

 peptonization seen so frequently in this material. 



Morphology. These organisms are identical morphologically 

 with Bacillus cereus. In young cultures 6 to 24 hours old, on 

 plain agar, they have round ends and measure 0.5 to 0.75 by 

 2.25 to 4 microns. The protoplasm may be homogeneous or 

 may show globular bodies of various dimensions. On glucose 

 agar the globular bodies are much more abundant and give the 

 organism a characteristic appearance. Here the rods measure 

 0.75 to 1 by 2.5 to 4 microns. (Figs. 28, 29, and 30.) 



Motility. Actively motile in young cultures. 



Staining properties. Gram-positive. 



Spore formation. Spores are formed readily on plain and on 

 glucose agar. They are abundant in 24 to 48 hours and have 

 the same appearance as the spores of Bacillus cereus. They are 

 usually central or sUghtly excentric and a trifle wider than the 

 organisms from which they spring thus bulging the rods some- 

 what. The free spores may retain equal or unequal bits of 



