NOTES 707 



component parts of a clock or other complicated machine are by no means all alike 

 It should be remarked that those who propound or accept theories of protoplasmic 

 structure are forced to associate all manifestations of vital activity in the elucidation 

 of which their theories are intended to assist -with these ultimate structural ele- 

 ments, although they are unable to make any definite statements concerning the 

 internal structure of the elements themselves. But we learn nothing concerning the 

 causes of vital activity by recognising ultimate protoplasmic particles, unless we 

 understand the structure of these particles and its relation to the various functions 

 of the living substance. The existing theories of protoplasmic structure therefore 

 do not explain a single manifestation of vital activity; all they do is to transfer 

 the fundamental problem to another plane of argument. Such speculations neverthe- 

 less have their uses, inasmuch as they help to define the limitations of our knowledge, 

 so far as the structure of living matter is concerned. Cf. Flemming : Arch. mikr. 

 Anat, 18, 1880. Id. ibid. 20, 1881. Id. Zellsubstanz, Kern- und Zellteilung. 

 Leipzig, 1883. Schmitz : Sitzb. niederrhein. Ges. 1880. De Vries : Intracellular 

 Pangenesis, Jena, 1889. Altmann : Die Elementarorganismen, Leipzig, 1890. 

 Weismann : Das Keimplasma, Jena, 1892. Wiesner : Die Elementarstruktur, 

 Wien, 1892. In recent times, it is especially Strasburger and his pupils who have 

 published numerous pajjers on the subject of protoplasmic structure. The important 

 question, as to the extent to which the granular, fibrillar, reticulate or other structures 

 observed in fixed material represent artefacts, is dealt with in detail in A. Fischer's 

 Fixierung, Farbung und Bau des Protoplasmas (Jena, 1899). 



6. Berthold : Studien iiber Protoplasmamechanik, Leipzig, 1886. Butschli : 

 Untersuchungen fiber mikroskopische Schaume und das Protoplasma, Leipzig, 1892. 



7. Reinke u. Rodewald : Unters. Gott. 2, 1881 (Aethalium septicum). Schwarz : 

 Cohn's Beitr. 5, 1887. Czapek : Biochemie d. Pflanzen, 1, pp. 20 sqq. 



8. Protoplasmic streaming. De Vries : B.Z. 1885 (importance for translocation). 

 Ida Keller : Uber Plasmastrtimung, Zurich, 1890. Hauptfleisch : P.J. 24, 1892. 

 Kohl : Wigand's Botanische Hefte 1. 1885, and Noll : Arb. Wurzb. 3, pp. 496 sqq. 

 (arrangement of protoplasm in relation to curvature). Tangl : Sitzb. Wien, 90, 

 1884 (continuity of protoplasm). G. Haberlandt : Uber d. Beziehungen zwischen 

 Funktion u. Lage d. Zellkernes b. d. Pflanzen, Jena, 1887, pp. 102 .sr/r/. Heidenhain : 

 Sitzb. Wfirzb. 1897. Nestler : Sitzb. Wien, 107, 1898 (streaming induced by 

 traumatic stimulation). Bierberg : Flora, 99, 1908. 



9. Ectoplast and vacuolar membrane. Pfeffer : Osmotische Untei\suchungen 

 Leipzig, 1877. Id. Unters. Tub. 2, pp. 179 sqq. (absorption of aniline dyes). Abh. 

 sachs. Akad. 16, 1890, pp. 185 sqq. De Vries : P.J. 16, 1885, pp. 465 sqq. Went : 

 P.J. 19, 1888, pp. 275 sqq. Noll : Naturw. Rund. 1888, 4 and 5 (action of light 

 and gravity). Id. Arb. Wiirz. 3, 1888, p. 532. Nemec : Sitzb. Prag (experimental 

 production of vacuoles). Noll : Biol. Centr. 1903. 



10. Structure and composition of nucleus. Strasburger : t T ber Zellbildung und 

 Zellteilung (3rd ed.), 1880. Flemming : Zellsubstanz, etc. Zacharias : B.Z. 18SI 

 (chemical composition). Id. ibid. 1882, 1883, 1885, 1887. 



For the voluminous modern literature cf. Zimmermann : Morphologic u. Physio- 

 logic d. pflanzlichen Zellkernes, Jena, 1896. Hacker : Praxis u. Theorie d. Zellen- 

 u. Befruchtungslehre, Jena, 1899. 



11. Strasburger: Histol. Beitr. 5, Jena, 1893. Schwarz : Cohn's Beitr. 4. L884. 

 Zacharias : Flora, 1895 (Erg.-Bd.). 



