Schneider: HISTORY OF LEGUMINOUS ROOT NODULES. 135 



FOURTH PERIOD : PRELIMINARY INVESTIGATIONS RELATING 

 TO THE POSSIBLE AND PROBABLE PRACTICAL UTILITY OF 

 RHIZOBIA AND FUNCTIONALLY RELATED ORGANISMS. FROM 



SCHNEIDER (1893) TO . 



This period corresponds to a period of renewed activity on 

 the part of investigators. As far as known the first paper out- 

 lining a course of research and giving a preliminary report of 

 work done with regard to the possible practical utility of rhi- 

 zobia in agriculture appeared in 1893, followed in 1896 by the 

 preliminary reports of researches by Nobbe and Hiltner and 

 still later reports by Hartleb and Caran. So far no entirely 

 satisfactory results have been obtained, but it is hoped that in 

 the near future (five to ten years or more) satisfactory and con- 

 clusive results may be obtained which will initiate the fifth 

 period, namely the Economic Value of Rhizobia and Func- 

 tionally Related Organisms. 



For the benefit of those interested, it may be stated that nearly 

 all of the titles of literature of the fourth period (up to date) are 

 found in the following list. A few are found in the first and 

 second installments. 



TITLES OF LITERATURE. 



Aeby. Beitrag zur Frage der Stickstoffnahrung der Pflanzen. Bei- 



hefte Bot. Centralbl. 68 : 333. 1896. 

 Beijerinck and Van Delden. Ueber die Assimilation des freien Stick- 



stoffs durch Bakterien. Centralbl. f . Bak. und Parasitenk. 9 : 3- 



43. 1902. 

 Berard, Noel. Etudes sur la tuberisation (Doctorate Thesis). Rev. 



gen. de Bot. 14: 101. 1902. 

 Bernatsky, J. Beitrag zur Kenntniss der endotrophen Mykorrhizen. 



Termszetr. Fuzet, 88. 1899. 

 Billwiller, J. Bot. Centralbl. 63 : 153. 1895. 

 Britton, E. G., and Taylor, A. Life history of Schizaea pusilla. 



Bull. Torr. Bot. Club, 28: 1-19. 1901. 

 Buhlert, H. Untersuchungen iiber des Artenheit der Knollchen- 



bakterien der Leguminosen und iiber die Landwirthschaftliche 



Bedeutung dieser Frage. Halle. 1902. 

 Chodat, R., and Lendner, A. Sur les mycorhizes du Listera cordata. 



Bull. d. 1'Herb. Boiss. 4 : 265-272. 1896. 

 Conn, H. W. Agricultural Bacteriology. Blakiston's Son and Co. 



1901. 



