Literature and Notes. 183 



30. Cohn n. Mendelssohn in Beitr. z. Biol. d. Pflanzen, III. 



31. W. Engelmann in Bot. Ztg., 1881, p. 441. 



32. W. Pfeffer, in Unters. a. d. Bot. Inst. ^. Tubingen, I, Heft 3. 



33. J. Tyndall in Phil. Trans, of the Royal Soc, London, 166 (1876), 

 167 (1877). The latter paper especially contains the statements with respect 

 to fractionating sterilisation. 



34. J. Wortmann in Zeitschr. f. physiol. Chemie, VI, p. 287. 



35. I still keep to the classification and nomenclature founded on Cohn's 

 divisions. It is better to treat what is imperfect as imperfect than to give it 

 the appearance of being perfect, and so cheat oneself and the beginner into 

 belief in a state of things which does not really exist. This might also be 

 said in criticism of some of the most recent attempts at improvement, but 

 further discussion of these would be out of place here. We have not yet 

 accomplished that which is an indispensable condition for any real advance 

 in classification, namely, a tolerably continuous morphological examination 

 of the individual species, — I do not mean of all existing species, but only of 

 such as at present pass for being ' described,' — whether collective or ' bad ' 

 species. Such an examination might be made with the material which we 

 at present possess, but this has not yet been done. 



36. W. Zopf, Zur Morphol. d. Spaltpflanzen, Leipsic, 1882 ; — Id., Entwick- 

 lungsgeschichtl. Unters. ii. Crenothrix polyspora, die Ursache d. Berliner 

 wassercalamitat, Berlin, 1879 ; — Id. in Monatsber. d. Berliner Acad., 

 Marz 10, 1881. 



37. E. Warming, Om nogle ved Danmarks Kyster levende Bacterier, in 

 Vidensk. Meddelelser fra d. naturhist. Forening, Kjbbenhavn, 1875. — A. 

 Engler, Die Pilzvegetation d. weissen od. todten Grundes d. Kieler Bucht, 

 in Ber. d. Commiss. z. Erforschung d. deutschen Meere, IV. 



38. P. van Tieghem, Sur la fermentation ammoniacale, in Compt. rend. 

 LVIII (1864), p. 211. — V. Jacksch in Zeitschr. f. physiolog. Chemie, V 

 (1881), p. 395. — Leube, Ueber d. ammoniakal. Hamgahrung. in Virchow's 

 Archiv, C, p. 540. 



39. Schlbssing u. Muntz in Compt. rend. LXXXIV, p. 301 ; LXXXIX, 

 pp. 91, 1074. 



40. Pasteur in Compt. rend. LIV, p. 265; LV, p. 28; — Id., Etudes sv.r 

 le vinaigre, Paris, 1868. 



41. V. Nageli, Theorie d. Gahrung, Miinchen, 1879. 



42. E. C. Hansen, Beitr. z. Kenntn. d. Organismen welche, in Bier u. 

 BierwUrze leben, in Meddelelser fra Carlsberg Laboratoriet, I, Kopenhagen, 

 1882. 



43. Pasteur in Compt. rend. LII, p. 344. 



44. P. van Tieghem, Leuconostoc, in Ann. d. sc. nat. s^r. 6, VII. 



45. F. Hueppe, Unters. ii. d. Zersetzung d. Milch durch Mikroorganismen, 

 in Mittheil. a. d. k. Reichsgesundheitsamt, II, 309, with a full account of 

 the history and literature. 



46. E. Kern, Ueber ein Milchferment aus dem Kaukasus, in Bot. Ztg., 



