512 C. A. LAUBACH, J. L. RICE AND W. W. FORD 



Glucose litmus agar colonies. Colony formation is very slow 

 and the colonies only appear within 48 hours. They are similar 

 to those on agar but less profuse. At times a slight wrinkling 

 occurs. 



Gelatin stab Very slow surface liquefaction. 



Gelatin colonies. The colonies are definitely circumscribed, 

 gray and moist, under the low power of the microscope showing 

 finely granular centers surrounded by small gray rings. Beyond 

 the rings there are other granular areas the outer borders of 

 which consist of dense gray rings. A very peculiar odor like that 

 of semen plus some aromatic radical occurs in gelatin. 



Broth. Peculiar pellicle made up of discrete colonies which 

 sink to the bottom. There is also a slight turbidity. 



Peptone. Growth similar to that in broth. 



Potato. The growth is dull, moist, gray, granular and finely 

 wrinkled. A slight lustre appears which becomes more pro- 

 nounced as the medium becomes drier. 



Litmus milk. Within 24 hours there is a complete reduction of 

 the litmus with an alkaline ring at the surface. A soft coagulum 

 is formed within 24 hours which is somewhat firmer than the 

 €oagulum formed by other spore-bearing organisms. Peptoniza- 

 tion begins after 48 hours and requires a considerable period be- 

 fore it is completed. The fluid remaining is straw-colored. 



Blood serum. The growth is grayish, moist, non-spreading and 

 not profuse. Within 96 hours it becomes finely wrinkled. 



Fermentation tubes. Glucose : there is a heavy pellicle formed 

 and a turbid growth in the bowl and neck of tube. If litmus is 

 present it is reduced in the closed arm. Also a turbid growth is 

 found in this arm. Reaction acid. 



Saccharose: a similar condition is apparent with little or no 

 acidity. 



Lactose : there is the same reaction with a slight alkalinity. 



Thermal death point. The spores survive 12 pounds pressure in 

 the autoclave but are destroyed by 15 pounds pressure. They 

 are destroyed by one hour's steaming in the Arnold sterilizer. 



