468 Hen- R. S. Bev&li on the 



b' 



(1884), Strasbui-ger * (1884), Weismann t (1885), Kbl- 

 liker X (1885), van Beneden § (1887), Weigert |1 (1887), and 

 Boveri^ (1889). Kolliker, in his ' Handbuch der Gewebe- 

 lehre' (6 Aufl., 1889), states the theory with great confi- 

 dence; and in 1890 Biltschli** also, who formerly held 

 similar views to my own on tlie question, was converted to it 

 in consequence of an experiment by Boveri, which will be 

 discussed more closely below. Only isolated sceptics de- 

 clared from time to time in quite general terms that the 

 positive foundations of this hypothesis were too weak ; thus 

 this view was already expressed by Hensenft i^ ^^^^ J^^^ 

 1885, and subsequently also by Whitman J| and _Wal- 

 deyer§§ ; these remarks, however, were passed over in silence 

 by the representatives of the " Theory." So far as I am 

 aware no one has as yet expressed himself in emphatic oppo- 

 sition to the theory; this is indeed intelligible when we con- 

 sider how great is the weight of authority by which it is 

 supported. 



In the first place let us draw attention to the important 

 difference between the original idea of Nageli |lll upon the 

 subject of idioplasm and nutritive plasm in their relation to 

 heredity and the ordinary theory which is here under discus- 

 sion. From the fact that spermatozoon and ovum, in spite of 

 their enormous difference in size, take an equal share in the 

 transmission of parental characters, Nageli concluded that 

 the matters which are of importance for the phenomenon of 



* Strasburger, ' Neue Untersucliimgen liber den Befrucbtungsvorgang 

 bei den Pbanerogamen als Grnndlage fiir eiue Theorie der Zengnng ' 

 (Jena, 1884) ; ' iJeber Kern- und Zelltbeilung im Pflanzenreiche, nebst 

 einem Anbang iiber Befruebtung ' (Jena, 1888). 



t Weismann, ' Die Kontinuitat dea Keimplasmas als Grnndlage einer 

 Tbeorie der Vererbuug ' (Jena, 1885). 



X Kolliker, " Die Bedentuug der Zellkerne fiir die Vorgange der Verer- 

 bung," Zeitschr. f. wiss. Zool., 42 Bd. (1885). 



§ E. van Beneden and A. Neyt, " Nouvelles recberclies sur la ftconda- 

 tion et la division mitosiqne cbez 1 Ascaride vieffalocephale," Bull, de 

 I'Acad. de Belgique, s6v. S, t. xiv. (1887). 



II Weigert, " Neue Vererbungstbeorien," Scbmidt's Jahrb. d. gesamm- 

 teu Medicin, 215 Bd. (^887). 



51 Boveri, "Ein gescblecbtlicb erzeugten Orgauismiis obne mutter- 

 leieben Antbeil," Sitzungsber. d. Ges. f. Morpbol. u. Pliysiol. in Miincben, 

 5Bd. (1889)._ 



** Biitscbli, ' Ueber den Ban der Bakterien u. verw. Organismen ' 

 (Heidelberg, 1890). 



tt V. Hensen, "Die Grundlagen der Vererbung nacli dem gegen- 

 wJirtigen Wissenskreis," Landwirtbscb. Jalirbiicber, 14 Bd. (1885). 



XX Whitman, " Tbe Seat of Formatis^e and Regenerative Energy," 

 Joiu-nal of Morphology, vol. ii, (1888). 



§§ Waldeyer, " Ueber Karyokinese und ibre Beziehungen zu den Be- 

 fruchtungsvorgfingen," Arch. f. mikr. Anat., 32 Bd. (1888). 



nil Nageli, * Mecbaniscb-pbysiologische Theorie der Abstammiings- 

 lehre ' (Miincben, 1883). 



