June, '34] burnside : bacteria associateu with European foulbrood 665 



in some respects differed from it. Whether these are different species 

 or belong to a group of which B. eurydice is a representative has not been 

 definitely determined." Concerning methods of culture White further 

 says : "Incubation must be carried out at room temperature. Growth of 

 the species is always slow and never luxuriant." In view of the writer's 

 observations it seems probable that the culture described by White as 

 B. eurydice and cultures which "in some respects differed from it" may 

 have been asporogenic variants of B. alvei. 



The variability of B. alvei in morphology and cultural characteristics 

 appeared to depend upon the physiological condition of the organism as 

 well as upon the culture medium. To retain viability of cultures frequent 

 transfers were necessary. The description of the organism given below 

 is of cultures produced as follows : Agar slant cultures of sporogenic 

 B. alvei were prepared from isolated colonies. A water suspension of 

 spores was boiled for 3 to 5 minutes, after which the organism was, cul- 

 tured by transferring for 10 generations in potato broth. Cultures pre- 

 pared from isolated colonies on agar plate by transfer to nutrient agar on 

 which sporulation is ordinarily prompt were then asporogenic at room 

 temperature. 



Glucose-agar plate. — Colonies slightly convex and rounded with uni- 

 form outline, 1 to 2 mm in diameter, grayish by reflected light, bluish 

 gray by transmitted light ; under a binocular appearing very light brown 

 and finely granular. 



Morphology. — Variable; rods nonmotile and asporogenic, occurring 

 singly, in pairs, or in chains, ends rounded ; protoplasm homogeneous or 

 granular or broken ; smaller and more slender than sporogenic B. alvei 

 in some cultures, of equal dimensions in others. 



Staining properties. — Stained readily with the usual dyes and Gram- 

 negative ; gra:nules sometimes darkly staining and Gram-positive. 



Oxygen requirements. — Growth Occurring under anaerobic conditions 

 but more luxuriant in the presence of air. 



Bouillon. — Medium slightly clouded after 48 hours, a slightly viscid 

 sediment forming slowly at bottom of tubes. 



Sugars. — With the usual sugars acid but no gas produced ; both arms 

 of tube clouded, but growth most luxuriant in open arm; litmus dis- 

 charged. 



Brood filtrate. — In some cultures brood filtrate added to the medium 

 increased growth, but in other cultures no effect observed ; growth also 

 variable in water solution of filtrate. 



Milk.- — Slight growth with little or no change apparent in either litmus 

 milk or plain milk. 



