[9] Winogradsky, loc. cit., p. 163 and ff.

[10] Godlewski, E., Anz. d. Akad. d. Wissensch. in Krakau, 1892, 408; 1895, 178.

[11] Nathanson, Mitteil. d. zool. Sta­tion, Neapel, 1902.

[12] Beijerinck, M., Folia Microbiologica, 1914, iii., 91.

[13] Ernst, A., The New Flora of the Volcanic Island of Krakatau, Cambridge, 1908.

[14] Euler, H., Pflanzenchemie, 1909, ii. and iii., 140.

[15] This fact was thoroughly established by Mendel and Osborne. A summary of their work is given in Underhill, F. P., Physiology of the Amino Acids, 1916.

[16] Van Slyke, D. D., and Cullen, G. E., Jour. Biol. Chem., 1914, xix., 141.

[17] Hill, C., Jour. Chem. Soc., 1898, lxxiii., 634.

[18] Armstrong, E. F., Proc. Royal Soc., 1905, B. lxxvi., 592.