Section IV., 1906. [157] Trans. R. S. C. 



XII. — The Nodule Organism of the Leguminosae — Its Isolation, 

 Cultivation, Identification and Com.mcrcial Application. 



By F. C. Hareison, Bacteriological Laboratories, The Macdonald Col- 

 lege, Ste. Anne de Bellevne, Que., 



and B. Barlow^ Bacteriological Department, Ontario Agricultural 

 College, Guelph, Ont. 



(Read May 23rd, 190G.) 



We shall endeavour to present in as brief a form as possible, the 

 results of some two years' study on the nodule organism of the Legum- 

 inosae. This work was primarily undertaken from the economic stand- 

 point, but a number of interesting scientific data were obtained, and 

 are incorporated in this paper. The more practical aspects of the 

 subjects have already been published as a bulletin by the Ontario 

 Department of Agriculture, under the title of " Co-operative Experi- 

 ments with Xodule-forming Bacteria" (Toronto, March, 1906). 



The various subject headings of this paper are as follows: — 



1. Occnrrence of nodules. 



2. Papilionaceae, from which Ps. radicicola has been isolated. 



3. Media for the culture of Ps. radicicoTa and for the growing of 



legumes. 



4. Isolation of Ps. radicicola. 



5. Colony formation. 



6. Growth of Ps. radicicola on various media. 



7. Morphology. 



8. Staining reactions. 



9. Viability. 



10. Cultures of Leguminosae in flasks containing ash-maltose-agar. 



11. Preparation and distrilnition of nitro-cultures. 



12. Co-operative experiments. 



1. Occnrrence of Nodules. — ^Ye have examined upwards of thirty 

 foreign economic species of Leguminosae of the sub-order Papilionacas, 

 exclusive of some twenty-four species and varieties of the genus Yicia, 

 also a number of native species. ISTodules were formed on the roots 

 of all these with the exception of two species, — Cicer ariotinum and 

 Galega officinalis. The peculiar spongy white roots of Galega were 

 examined by crushing and staining, but no bacteria were found, and 

 there is, of course, the probability that the appropriate variety of Ps. 

 radicicola was not prasent in the soil. 



