234 SENESCENCE AND REJUVENESCENCE 



Such reproduction is possible only where the isolated part is capable 

 of reacting to the isolation by dedifferentiation and reconstitution. 

 According to this conception, agamic reproduction in organisms 

 results in one way or another from the physiological or physical iso- 

 lation of a subordinate part from the influence of the dominant part. 

 At first glance game tic or sexual reproduction appears to be a totally 

 different kind of reproduction, but, except for the occurrence of 

 fertilization, it is in reality very similar to the agamic process. 

 Before taking up the problem of sexual reproduction, however, it is 

 necessary to consider the relation between individuation, agamic 

 reproduction, and the age cycle. 



REFERENCES 



BlEDERMANN, W. 



1903. "Elektrophysiologie," Ergebn. d. PhysioL, Jhg. II, Abt. II. 



BORUTTAU, H. 



1901. "Die Aktionsstrome und die Theorie der Nervenleitung," Arch. 

 f. d. ges. PhysioL, LXXXIV. 



BRESSLAU, E. 



1904. "Beitrage zur Entwicklungsgeschichte der Turbellarien: I, Die 

 Entwicklung der Rhabdocolen und Alloiocolen," Zeitschr. f. wiss. 

 ZooL, LXXVI. 



CHILD, C. M. 



19070. "An Analysis of Form Regulation in Tubularia: I, Stolon- 

 Formation and Polarity," Arch. f. Entwickelungsmech., XXIII. 



19076. "An Analysis, etc.: IV, Regional and Polar Differences in the 

 Time of Hydranth-Formation as a Special Case of Regulation in 

 a Complex System," Arch. f. Entwickelungsmech., XXIV. 



1907^. "An Analysis, etc.: V, Regulation in Short Pieces," Arch. f. 

 Entwickelungsmech., XXIV. 



1910. "Physiological Isolation of Parts and Fission in Planaria," Arch, 

 f. Entwickelungsmech., XXX (Festband f. Roux), II. Teil. 



19110. "Die physiologische Isolation von Teilen des Organismus," Vortr. 

 und Aufs. u. Entwickelungsmech., XI. 



19116. "Studies on the Dynamics of Morphogenesis and Inheritance in 

 Experimental Reproduction: II, Physiological Dominance of 

 Anterior over Posterior Regions in the Regulation of Planaria 

 dorotocephala," Jour, of Exp. ZooL, XI. 



191 ic. "Studies, etc.: Ill, The Formation of New Zooids in Planaria 

 and Other Forms," Jour, of Exp. ZooL, XI. 



