138 



BACTERIA IN RELATION TO PLANT DISEASES. 



It must be left an open question whether de Rossi's results are to be regarded as something 

 entirely new and revolutionary or only as a record of certain difficulties which would not have been 

 encountered by another investigator. In some ways, at least, the organism which he finally isolated 

 is not unlike what has been considered in recent years by many bacteriologists as the root-nodule 

 organism. 



Regarding his inferences two or three countering ones may be made : 



(i) He entered the nodules through an unsterilized surface and, hence, the various sorts of colonies which grew 

 promptly on his plates may have come from the surface and are not necessarily what others have mistaken 

 for the root-nodule organism. Indeed, it is possible that all of these early difficulties might have been 

 avoided by a proper technique of entrance. 



(2) His failures to obtain any growth of the right organism on ordinary nutrient gelatin are exactly what a careful 

 study of the previous literature of the subject should have led him to expect. Beyerinck long ago divided 

 the root-nodule organisms into two groups those which grow well on ordinary media, e. g., beef extract- 

 peptone-gelatine, and those which do not, and stated that the organism from Vicia faba belonged to the 

 second class. 



(3) The very slow growth of the right organism on gelatin containing Vicia faba extract may also have been due 

 to the restraining influence of an improperly prepared culture medium, i. e., one made from an inferior 

 strongly acid gelatine, or one containing too much chloride, too much peptone, or too strong an extract of 

 the green parts of the plant, or one boiled for too long a time. 



(4) Unless the experiments were duplicated several times with identical results we might assume that all of the 

 bacteroids were dead in the one case (scrapings from the agar surface to other media) and only a part of 

 them dead in the other case (scrapings from the agar surface to Vicia plants which became infected.) 



LITERATURE. 



Root-Nodule Organisms, including 



1866. Woronine, M. Ueber die bei der Schwarzerle 

 (Alnus glutinosa) und bei der gewohnlichen 

 Gartenlupine (Lupinus mutabilis) auftreten- 

 denWurzelanschwellungen. Mem.de TAcad. 

 Imp. de St. Petersbourg, Se. vn, T. x, 1866, 

 No. 6, pp. 1-13, 1 Taf. 



1873. Eriksson, J. Studier ofver Leguminonsernas 

 rotknolar. Acta Universitatis Lundensis. 

 Lunds Universitets Ars-skrift, 11, Afdelningen 

 for Mathematik och Naturvetenskap, Tome 

 x, Lund, 1873, No. vin, pp. 1-30, 3 plates. 

 Ref. Bot.Zeitung, 1874, Cols 381-384. 



1877. de Vries, Hugo. Keimungsgeschichte des 

 roten Klees. Berlin, Landw. Jahrb., Bd. VI, 

 1877, pp. 466-512. 



1879. Frank, B. Ueber die Parasiten in den Wurzel- 

 anschwellungen der Papilionaceen. Bot. 

 Zeitung, Bd. 37, 1879, cols. 376-387 and 

 394-399- 



1879. PrilliEux, Ed. Sur la nature et sur la cause 

 de la formation des tubercules qui naissent sur 

 les racines des Legumineuses. Bull, de la 

 Soeiete Botanique de France, T. 26, 2nd Ser., 

 1879. pp. 98-106. 



1879. Kny, L. Zu dem Aufsatze des Herrn Prof. B. 

 Frank, " Ueber die Parasiten in den Wurze- 

 anschwellungen der Papilionaceen." Verhand- 

 lungen des Bot. Ver. der Prov. Brandenburg, 

 Sitzungsberichten 1879, pp. 115-118. 



1884. SchindlER, F. Zur Kenntnis der Wurzel- 



knollchen der Papilionaceen. Botan.Centralb., 

 Bd. xvm, 1884, pp. 84-88. 



1885. Brunchorst, J. Ueber die Knollchen an den 



Leguminosenwurzeln. Berichte der deutschen 

 botan. Gesellsch., Bd. Ill, 1885, pp. 241-257. 



Brunchorst considered the "bacteroids' as products of 

 the protoplasm of the plant. 



1885. MollER, H. Ueber Plasmodiophora alni. 

 Berichte der deutschen bot. Gesellsch., Berlin 

 1885, Bd. in, pp. 102-105. 



1885. BerthElot, MarcELUN. Fixation directe de 

 l'azote atmospherique libre par cert:..n 

 terrains argileux. Compt. Rend, des se. de 

 l'Acad. des Sci., Paris, 1885. T. 101, pp. 

 775-784- 



some more or less related topics. 



1885. SchindlER, F. Ueber die biologische Bedeutung 



der Wurzelknollchen bei den Papilionaceen. 

 Journ. f. Landw., 1885, Bd. xxxin, pp. 325- 

 336. 



1886. BerthElot, Marcellin. Sur le dosage du 



carbone organique content! dans les sols qui 

 fixent l'azote libre. Compt. Rend, des se. de 

 l'Acad. des Sci., Paris, 1886. T. 102, pp. 

 951-954- 



1886. BerthElot, ET Andre. Observations relatives 

 a la proportion et au dosage de l'ammoniaque 

 dans le sol. Compt. Rend.de se. des l'Acad. 

 des Sci., T. 102, pp. 954-956, and T. 103, 

 pp. 1101-1104. 



1886. Frank. Die Stickstoff-Frage vor, auf und nach 

 der Naturforseher-Versammlung zu Berlin. 

 Deutsche landw. presse, 1886, Nr. 97, pp. 

 629-630. 



1886. HellriEgel. Welche Stickstoffquellen stehen 

 der Pflanze zu Gebote? Tageblatt der 59 

 Versamml. deutseher Naturf. u. Aerzte in 

 Berlin, 1886, p. 290. 



1886. SchloESIng, Th. Remarques sur la communi- 

 cation de MM. Berthelot et Andre, inseiree 

 aux "Compt. Rend." de la derniere seance, 

 relative a la proportion et au dosage de 

 l'ammoniaque dans les sols. Compt. Rend. 

 de se de l'Acad. des Sci., Paris, 1886. T. 102, 

 pp. 1001-1002, 1217-1221. 



1886. Strecker, W. Die Bereieherung des Bodens 

 durch den Anbau "bereichernder" Pflanzen. 

 Journ. f. Landw., 18S6, Bd. xxxiv, pp. 1-82. 



1886. Brunchorst, J. Ueber einige Wurzelansch- 



wellungen, besonders diejenigen von Alnus 

 und den Elaeagnaceen. Untersuch. a. d. bot. 

 Inst, zu Tubingen, Leipzig, 1886, Bd. 11, pp. 

 151-177. 1 Tafel. 



1887. Wilfarth. Ueber Stickstoffaufnahme der 



Pflanzen. Tageblatt der 6oVersamml. deutseher 

 Naturf, u. Aerzte zu Wiesbaden, 1887. See 

 also Die landw. Versuchs-Stationen, 1887, Bd 

 xxxiv, pp. 460. 



