BV R. GREIG SMITH. 673 



Of the other bacteina and moulds of the nodule there are none 

 that call for any special attention. When taken from the nodule 

 they are chiefly capsulated gelatine-liquefying bacteria. Bad. 

 Jluorescens liquefaciens was obtained from the nodules of one pea 

 plant in goodly amount; but since it was not found in any other, 

 its presence was purely accidental. Stutzer's Hy2)homicrohium 

 pccurs very frequently as an impurity in the partially pure 

 colonies of the nodule former. 



The following are the points which this investigation has 

 decided : — 



1. The nodule organism is a yeast and possesses a vacuole. 



"2. Frank's designation lUiizohium hi/umin(>f<arum is better than 

 Beijerinck's Bacterium radicicola. 



3. The organism multiplies by budding, which, together with 



the presence of a more of less persistent mucilaginous 

 capsule, causes the single or compound organism to assume 

 a variety of shapes. 



4. The vigorous forms are motile, the motility being due to a 



single, terminal, tufted flagellum. 



5. A faintly acid glucose medium is best adapted to its growth. 



6. The organism does not fix nitrogen in artificial media. 



7. Bac. meyatherinm usually accompanies Rhizohium in the 



nodules. 



8. Other bacteria found iu the nodules are probably accidental. 



EXPLANATION OF PLATES. 



Magniticatioii 1500. Culture medium, peptone-glucose fluid. Numbers. 

 3-7 stained with Coerner- Fischer mordant. 

 Fig. I. — Double cell and pronounced vacuole. 

 Fig. 2. — Groups of budding and vacuolated cells. 

 Fig. 3. — Budding cells. 



Figs. 4-7. — Cells with flagellum appendages. 



Fig. 8.- Cells in Me<i(ithcyiinn-Ehizohiu)ii culture showing Rhizohium cells. 

 in large capsule and also in thin branching capsule. 



