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: 
(1) 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. 
avoided by a proper technique of entrance. 
Indeed, it is possible that all of these early difficulties might have been 
(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, 7. 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 some more or less related topics. 
1866. WoRONINE, M. Ueber die bei der Schwarzerle 
(Alnus glutinosa) und bei der gewéhnlichen 
Gartenlupine (Lupinus mutabilis) auftreten- 
den Wurzelanschwellungen. Mém.de l’Acad. 
Imp. de St. Petersbourg, Sé. vn, T. x, 1866, 
No. 6, pp. 1-13, 1 Taf. 
1873. Eriksson, J. Studier 6fver Leguminonsernas 
rotknélar. Acta Universitatis Lundensis. 
Lunds Universitets Ars-skrift, 1, Afde!ningen 
for Mathematik och Naturvetenskap, Tome 
x, Lund, 1873, No. vii, pp. 1-30, 3 plates. 
Ref. Bot. Zeitung, 1874, Cols. 381-384. 
1877. DE Vries, Huco. Keimungsgeschichte des 
roten Klees. Berlin, Landw. Jahrb., Bd. v1, 
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. Pri1eux, Ep. Sur la nature et sur la cause 
de la formation des tubercules qui naissent sur 
les racines des Légumineuses. Bull. de la 
Société Botanique de France, T. 26, 2nd Sér., 
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- 
knéllchen der Papilionaceen. Botan. Centralb., 
Bd. xv, 1884, pp. 84-88. 
1885. Bruncuorst, J. Ueber die Knéllchen an den 
Leguminosenwurzeln. Berichte der deutschen 
botan. Gesellsch., Bd. 01, 1885, pp. 241-257. 
Brunchorst considered the ‘bacteroids’ as products of 
the protoplasm of the plant. 
1885. Mo..er, H. Ueber Plasmodiophora alni. 
Berichte der deutschen bot. Gesellsch., Berlin 
1885, Bd. 111, pp. 102-105. 
1885. BERTHELOT, MARCELLIN. Fixation directe de 
l’azote atmosphérique libre par certain 
terrains argileux. Compt. Rend. des sé. de 
l’Acad. des Sci., Paris, 1885. T. 101, pp. 
775-784. 
1885. 
1886. 
1886. 
1886. 
1886. 
1886. 
1886. 
1886. 
1887. 
ScHINDLER, F. Ueber die biologische Bedeutung 
der Wurzelknéllchen bei den Papilionaceen. 
Journ. f. Landw., 1885, Bd. xxx, pp. 325- 
336. 
BERTHELOT, MARCELLIN. Sur le dosage du 
carbone organique contenu dans les sols qui 
fixent l’azote libre. Compt. Rend. des sé. de 
l’Acad. des Sci., Paris, 1886. T. 102, pp. 
951-954. 
BERTHELOT, ET ANDRE. Observations relatives 
a la proportion et au dosage de l’'ammoniaque 
dans le sol. Compt. Rend. de sé. des l’Acad. 
des Sci., T. 102, pp. 954-956, and T. 103, 
pp. 1101-1104. 
FRANK. Die Stickstoff-Frage vor, auf und nach 
der Naturforscher-Versammlung zu Berlin. 
Deutsche larftiw. Presse, 1886, Nr. 97, pp. 
629-630. 
HELLRIEGEL. Welche Stickstoffquellen stehen 
der Pflanze zu Gebote? Tageblatt der 59 
Versamml. deutscher Naturf. u. Aerzte in 
Berlin, 1886, p. 290. 
ScHLOESING, TH. Remarques sur la communi- 
cation de MM. Berthelot et André, inséirée 
aux ‘‘Compt. Rend.” de la derniére séance, 
relative a la proportion et au dosage de 
l’ammoniaque dans les sols. Compt. Rend. 
de sé de l’Acad. des Sci., Paris, 1886. T. 102, 
Pp. 1001-1002, 1217-1221. 
STRECKER, W. Die Bereicherung des Bodens 
durch den Anbau “bereichernder” Pflanzen. 
Journ. f. Landw., 1886, Bd. xxxiv, pp. 1-82. 
Bruncuorst, J. Ueber einige Wurzelansch- 
wellungen, besonders diejenigen von Alnus 
und den Elaeagnaceen. Untersuch. a. d. bot. 
Inst. zu Tiibingen, Leipzig, 1886, Bd. m1, pp. 
151-177. 1 Tafel. 
WILFARTH. Ueber Stickstoffaufnahme der 
Pflanzen. Tageblatt der6oVersamml.deutscher 
Naturf, u. Aerzte zu Wiesbaden, 1887. See 
also Die landw. Versuchs-Stationen, 1887, Bd. 
XXXIV, pp. 460. 
