154 



BACTERIA IN RELATION TO PLANT DISEASES. 



By careful washing, the spheres of Volvox were freed from pond water and placed by means of a 

 sterile platinum loop in a sterile nutrient solution consisting of 200 cc. of water containing 4.0 mannit, 

 0.1 of potassium phosphate, 0.05 of magnesium phosphate, and 0.3 of calcium carbonate. At the 

 end of 10 weeks this solution contained 11.6 mg. of combined nitrogen. The only possible source 

 of this nitrogen was the assimilation of the atmospheric nitrogen, absorbed in the water. Azotobacter 

 had developed abundantly. 



The infection with Azotobacter was possible only through the introduction of Volvox to the 

 surface of which some of these organisms were clinging. 



Reinke's conclusion is that Azotobacter, while drawing its carbon in organic form from the 

 Volvox, furnished the latter with nitrogen compounds. He is convinced that this theory concerning 

 the source of nitrogenous compounds for both fresh and salt water algae is worthy of preference over 

 every other hypothesis. As a further support for his theory he mentions the fact, discovered by 

 Gerlach and Vogel, that the dry substance of Azotobacter contains 10 to 12 per cent of nitrogen. 



In 1904, Hugo Fischer published a short article on an assumed symbiosis between 

 Azotobacter and Oscillaria living on the ground. 



He obtained samples of dark green Oscillaria from different localities, and covered them 

 with a I per cent solution of mannit, according to Beyerinck's method. There was such a 

 rapid development of Azotobacter in pure culture that he was forced to assume an especially 

 favorable growth of it among the filaments, although he could not demonstrate it micro- 

 scopically. From this common occurrence together, he concludes that a symbiotic relation 

 exists by which the bacteria furnish nitrogen compounds to the algae taking in return from 

 their supply of carbohydrates. The earlier assumption, therefore, that the lower algae are 

 able to assimilate free nitrogen should, he thinks, be retracted. 



LITERATURE. 



iNSEcxrvoRous Plants. 



1875- 



1889. 



1890. 



1892. 



MoRREN, E. Observations sur les procedes in- 

 secticides des Pinguicula. Bull, de I'Acad. 

 Royale des sciences des lettres et des beaux- 

 arts de Belgique. Bruxelles, 1875, 2 ser. T. 

 XXXIX, pp. 870-881. 



TisCHUTKiN, N. Die RoUe der Bacterien bei der 

 Veranderung der Eiweisstoffe auf den Blattem 

 von Pinguicula. Berichte der d. bot. Ges., 1889, 

 Bd. VII, pp. 346-355. 



Dubois, R. Sur le pretendu pouvoir digestif du 

 liquide de I'ume des Nepenthes. Comptes 

 Rendusdesse.de I'Acad., des Sci., 1890, T. cxi, 

 PP- 315-317- 



TisCHUTKiN, N. ijber die Rolle der Mikroor- 

 organismen bei der Emahrung insektenfres- 

 sender Pflanzen. Acta Horti Petropolitani, 

 Vol. XII, No. I, 1892, pp. I to 19. See also 



Arbeiten d. St. Petersburger Naturf. Gesellsch., 

 1891, Abt. f. Bot., pp. 33-37, and Rothert in 

 Bot. Centralbl., Bd. uii, p. 322, Bd. L, p. 304. 



1897. Vines, S. H. Proteolytic Enzyme of Nepenthes. 



Annals of Botany, 1897, vol. xi, pp. 563-584. 



1898. Vines, S. H. The proteolytic enzyme of 



Nepenthes (11). Annals of Botany, 1898, vol. 

 XII, pp. 545-555. 



1899. Clautriau, Georges. La Digestion dans les 



Umes de Nepenthes. Mem. couronnes. Acad. 



roy. de Belgique, 1900, Tome ux, pp. 1-54. 



Bibliography of 31 titles. 

 1 90 1. Vines, S. H. The proteolytic enzyme of 



Nepenthes (in). Annals of Bot., 1901, vol. 



XV, pp. 563-573. 

 1 910. White, Jean. The proteolytic enzyme of 



Drosera. Proc. Roy. Soc, Bd. 83, Ser. B. 



562, 1910, p. 134-139. 



Hops. 



MoHL, Ant. Ueber die Bildung des Lupulins 

 und den Micrococcus humuli Launensis. 

 Osterreichisches Landwirtschaftliches Cen- 



tralbl., Heft V, i892,Jahrg. I, pp. 13-18, i page 

 of figures. See also AUg. Brauer-u. Hopfenzeit. 

 1892, Bd. 47, p. 753. 



Algae. 



1894. 



1896. 



1900. 



1903. 



KossowiTSCH, P. Untersuchungen uber die 

 Frage, ob die Algen freieii Stickstoff fixiren. 

 Botanische Zeitung, Jahr. 52, Leipzig, 1894, 

 Col. 97-116. 



BouiLHAC, Raoul. Sur la fixation de I'azote 

 atmosph^rique par I 'association des algues et 

 des bacteries. Compt. Rend, des se. de I'Acad. 

 des Sci., Paris, 1896, T. 123, pp. 828-830. 



Krcjger, W. und SchneidEwind, W. Sind 

 niedere, chlorophyllgriine Algen imstande, den 

 freien Stickstoff der Atmospharezuassimilieren 

 und den Boden an Stickstoff zu bereichern? 

 Landw. Jahrbiicher, Berlin, 1900, Bd. 29, pp. 

 771-804. 3 Taf. 



Reinke, J. Die zur Emahrung der Meeres- 

 Organismen disponiblen Quellen an Stickstoff. 



Berichte der deutschen botan. Gesellschaft, 

 Berlin, 1903, Bd. xxi, pp. 371-380. 

 1903. Reinke, Johannes. Symbiose von Volvox und 

 Azotobacter. Ber. d. d. bot. Ges., Berlin, 



1903. Bd. XXI, pp. 481-483. 



1903. Benecke, W., und Keutner, J. Uber stick- 



stoffbindende Bakterien aus der Ostsee. 

 Berichte der deutsch. botan. Gesellsch., 1903, 

 Bd. XXI, pp. 333-346, 4 figs. 



1904. Fischer, Hugo. Ueber Symbiose von Azoto- 



bacter mit Oscillarien. Centralbl. f. Bakt., 



1904, 2 Abt., Bd. XII, pp. 267-268. 



1904. BouiLHAC, ET Giustiniani. Sur des cultures de 

 diverses plantes supferieures en presence d'un 

 melange d'algues et de bacteries. Compt. 

 Rend, des s6. de I'Acad. des Sci., Paris, 1904, 

 Tome 138, pp. 293-296. 



