IOO BACTERIA IN RELATION TO PLANT DISEASES. 



The synonymy of Bact. leguminosarum (Frank) is as follows : 



Syn: Schinzia leguminosarum Frank (1879); 

 Bacillus radicicola Beyerinck (1888); 

 Cladochitrium tuberculorum Vuillemin (1888); 

 Bacterium radicicola Prazmowski (1889), Moeller (1892); 

 Phytomyxa leguminosarum Schroter (1889); 

 Rhizobium leguminosarum Frank (1890)?; 

 Bacillus ornithopi Beyerinck (1890); 

 Bacillus fabae Beyerinck (1890); 

 Rhizobium rnutabile 



Rh. curvum 



Rh. Frankii var. majus 



Rh. Frankii var. minus 



Schneider (1892); 



Rh. nodosum 



Rh. dubium 



Rhizobium sphaeroides Schneider (1894); 



Micrococcus tuberigenus Gonnermann (1894); 



Rhizobium Pasteurianum Laurent (earlier than 1899 according to Maze, but the writer has been unable 



to find the name in any of Laurent's papers). 



Bacterium (Rhizobacterium) japonicum Kirchner (1895) (applied to the soy-bean organism) ; 

 Rhizobium Beijerinckii Hiltner and Stormer (1903) (applied to organism causing the root-nodules 



of Lupinus, Ornithopus. and Soya) ; 

 Rhizobium radicicola Hiltner and Stormer (1903) (applied to organism causing the root-nodules of 



Pisum, Vicia, Phaseolus, etc.) ; 

 Pseudomonas radicicola Moore (1905). 



In 1906 Stefan suggested that the root-nodule organism is related to the Myxo- 

 bacteriaceae. 



In 1910, Peklo maintained it to belong with Actinomyces. 



SUMMARY OF LEADING PAPERS. 



From the hundreds of pages relating to root-nodules the writer has culled the following 

 statements : 



Apparently the first person to discover bacteria in the root-nodules was Woronine (1867). He 

 states that he made his examinations principally upon the common lupin of the gardens (Lupinus 

 mutabilis Lindley). He describes the nodule as composed of an interior parenchyma, an exterior 

 parenchyma, and a vascular system between the two, the cells of the interior parenchyma being 

 occupied by enormous numbers of small rods which he figures and describes as bacteria. His exact 

 statement respecting their classification is as follows: 



" In all these respects, they have the greatest resemblance to those organisms of doubtful nature 

 which have been designated under the names of Bacterium Duj., Vibrio Ehrbg., Zoogloea Cohn, etc., 

 and we may, without doing violence to the analogies, range them in the same class." 



His figures correspond very well to the facts as we now understand them, even to enlarge- 

 ment and shriveling of the nucleus (fig. 33) . 



The same paper deals with the enlargements on the roots of Alnus. In these he says he found 

 a fungus, described as Schinzia alni. 



Frank (1879) saw the bacterial filaments, sometimes ending in a sharp point in the middle of 

 the cell. To him they were hyphae. The "hyphae" and the small rods and branched bodies were 

 believed to be parts of the same fungus, although Frank was far from certain respecting this. This 

 paper is the one in which he first used the name Schinzia leguminosarum (column 397). 



Hellriegel and Wilfarth (September 20, 1886) demonstrated the great difference between the 

 nitrogen nutrition of grains and legumes and connected the latter with the presence of the root- 

 nodules. 



They made pot experiments, using quartz sand washed many times, nutrient solutions contain- 

 ing all the mineral elements necessary for growth except nitrogen, and watered with pure distilled 

 water (the first part of the distillate being rejected). Under these circumstances they found that the 

 crop of oats or barley was in direct proportion to the amount of nitrate of soda added. When no 

 combined nitrogen was added these grains soon showed nitrogen hunger and uniformly perished. 



Under the same conditions, i.e., nitrogen compounds withheld but all other foods added, peas 

 grew remarkably well and produced seeds. Many comparative experiments were made and the re- 

 sults were uniform. It was plain, therefore, that the peas did not obtain their nitrogen from the soil. 



