242 IVAN V. SHUNK 



immediately by one or two drops of solution B. The combination 

 was allowed to act at room temperature for two minutes, washed 

 in distilled water and the stain applied for two minutes. The 

 excess stain was washed off with water and the cover glass prepa- 

 ration dried and mounted in balsam. 



RESULTS OF STAINING 



The age of cultures of the organism from different legume 

 host plants made a considerable difference in the staining reaction. 

 It was sometimes necessary on this account to try cultures of 

 varying ages before successfully staining the flagella. The fol- 

 lowing table contains the data bearing on the source of the cul- 

 tures, their age at time of staining, and the number of flagella. 



DISCUSSION 



Manifestly the flagellation of the legume nodule bacteria is 

 of two t3T)es,. the single flagellate type and the peritrichic. In 

 every case in which the organisms possessed more than one 

 flagellum the arragement was peritrichic and in the case of those 

 with a single flagellum it was usually attached at the corner 

 rather than exactly at the end. This corner arrangement seems 

 to characterize the single flageUate type. In the case of organ- 

 isms of this type, more than one flagellum was never found, and 

 enough organisms were observed in each case so that there is no 

 doubt that one is the correct number, and that it is an entirely 

 different organism from the peritrichic type. Due to the break- 

 ing off of flageUa in handling, bacteria of the peritrichic type 

 showed an occasional organism with only one flagellum. For 

 the most part the peritrichic flagella were longer than the single 

 flagella and there was a tendency for the single flagella to be of 

 greater diameter than those of the other type. 



The present findings are in accord with those of Hansen (1919) 

 who has suggested that since the organisms from different 

 legumes have in some cases one flagellum, and in others several 

 flagella, we have really two groups of organisms based on these 

 differences of flagellation. Conn (1920) is of the opinion that the 



