152 



THE NATURE OF THE BACTEROIDS OF THE LEGU- 

 MINOUS NODULE AND THE CULTURE OF 

 RHIZOBIUM LEGUMINOSARUM. 



By R. Greig Smith, M.Sc, Macleay Bacteriologist to 

 THE Society. 



in a recent publication"^ L. Hiltner discusses the views of 

 Stutzer with regard to the nature of the bacteroids of the nodules 

 of the Leguminosoi. The generally accepted view is that the 

 bacteroids of the nodule are degenerate or involution forms of 

 Bhizobium leguminosarum. Stutzer considers that they represent 

 a higher and not a lower type of growth, and to this Hiltner 

 replies that he cannot see why they should be so considered. His 

 own view is that the bacteroids are simply enlarged bacteria. 



In a former paper f I showed that the branching forms were 

 really simple cells contained in a branching capsule. This is the 

 case both with the organisms in artificial culture and in the root 

 nodules. One has only to extract the colouring matter 

 from the capsule after staining a bacterial film to see the 

 simple cells within. There is no reason to suppose that the y or 

 the Y form is either degenerate or specialised; they are simply 

 single cells contained in the bulky mother capsule from which the 

 daughter cells are unable to escape until they have increased in 

 size and become stronger or until the capsular envelope has 

 become dissolved either partially or wholly by the fluids of the 

 plant tissue. 



* Hiltner, Centralblatt fiir Bakt. ii. Abt. vi. 273. 

 t These Proceedings, 1899, Part 4, pp. 653-673. 



