65S THE NODULE ORGANISM OF THE LEGUMINOS-E, 



Temperatuies from 22'-26° are most favouiable; the growth 

 ceases at 30". In bouillon, a slimy precipitate is formed, which 

 consists of rods and branched forms. Motility could not be 

 observed even in the smallest forms. 



Beijerinck,* from the nodules of Vicia lathyroides, obtained a 

 species of Bact. raclicieola, which in artificial media had a pro- 

 nounced capsule, forming threads and balls similar to the appear- 

 ances seen in nodule sections of some genera of Le(/i(minosfe. In 

 the capsule the I'ods do not assume the bactex'oidal form. 



(jronnermannf considered that the bacteriological research of 

 the nodule had been kept in the background; those who had 

 investigated the nodule question had done so from a botanical 

 and an agricultui-al-chemical point of \ie\v. Beijerinck had not 

 described his bacterium at all fully ; indeed, he mentioned the 

 ■organism as being ciliated, although he had not observed the 

 flagella. As a i-esult of his own researches, (lonnermann did not 

 consider the nodule to l^e produced by the stimulus of one organ- 

 ism alone, but to result from the action of se\eral. Out of nine 

 bacteria which he separated from sterile soil, in which nodules had 

 •been produced on plants by infection with cut nodules,! he found 

 two cocci which by themselves were capable of producing nodules 

 ■on leguminous roots. This is the first intimation that cocci may 

 produce the nodules, although Frank spoke of cocci which became 

 bacteria in the tissues, and Beijerinck claimed that Jiact. radicicnla 

 may assume the coccus, bacterium or spirillum form. 



Kleini^ claims to have proved nodule-formation on the lupin by 

 two bacteria, one allied to Bacterium Jiuorescens liqtiefaciens, and 

 the other a short, oval, non-motile bacterium, which stains deeply 

 at the ends and produces small colonies that slowly liquefy the 

 gelatine. 



It is evident that the bacterial flora of the leguminous nodule 

 may be very varied — a circumstance which is to be expected by 



* Beijerinck, II>i>L, xv. 728. 



t <Tonnermann, Centrall). fiir Bakt. 2 Abt. i. "200. 



X Kruse — Flugge, Die Microorganismen. 



S Klein, Ceatralb. fiir Bakt. 1 Abt. xvi. 840. 



