SPOB E-FORMING ORGANISM FROM IOWA 333 



no granules were discernible when stained with carbol fuchsin, 

 Loeffler's methylene blue or Albert's diphtheria stain. The vege- 

 tative cells stain readily with all of the stains mentioned. 



MOTILITY 



All of the 14 cultures were found to be motile when examined in a 

 hanging drop from a 16 hour, 37C. peptone water culture. 



SPORE FORMATION 



It has already been mentioned that spores were formed readily 

 on nutrient agar in 2 days at the body temperature; it is significant 

 to note, however, that spores could not be demonstrated in lactose 

 agar or milk even after long incubation. 



Three cultures were inoculated into lactose broth, lactose agar 

 and plain agar and incubated at body temperature for 48 hours. 

 No spores were visible in the lactose broth or lactose agar but they 

 were numerous on plain agar. 



On another occasion six cultures were inoculated into two batches 

 of litmus milk. Microscopic examination (Gram stain) after 4 days 

 and again after 10 days at 37C. did not show any spores although 

 the organism from these media was found to survive a temperature 

 of 92C. for 20 minutes. There was a marked tendency to granular 

 staining. 



Examination of four cultures on lactose (Andrade) agar, incubated 

 3 days at 37C. then stored for 2 weeks in the ice box also failed to 

 disclose any spores when stained by Gram's method. As in the 

 milk cultures there was a marked tendency to granular staining 

 and the cells were resistant to heat, surviving 92 for 20 minutes. 



We feel therefore that the organism does not form recognizable 

 spores readily, if at all, on lactose media. This is of some practical 

 significance in water work as it indicates the improbability of de- 

 tecting spores of this bacillus and thereby differentiating it from 

 B. coli by examination of stained mounts from confirmatory lactose 

 agar plates. 



TEMPERATURE RELATIONSHIPS 



Growth is much more luxuriant on agar at 37C. than at 20 to 

 22C. At the lower temperature 4 days may be necessary before 

 any growth is visible. No growth was visible after one week at 

 53C. 



